WIP: Z: Add l2i case for TM reduction

[sarwat12]

This draft PR updates the function generateTestUnderMaskIfPossible to add the case of l2i for pattern matching trees in order to reduce a specific set of instructions into TM + BRC in memory test.

The following is an example tree with a specific pattern with an ificmpne node against zero, with an iand child. The iand child with l2i first child, and constant second child.

n22n     (  0)  ificmpne --> block_3 BBStart at n20n ()                                              [     0x3ff69802fe0] bci=[-1,4,180] rc=0 vc=538 vn=- li=2 udi=- nc=2 flg=0x20
n17n     (  1)    iand (X>=0 cannotOverflow )                                                        [     0x3ff69802e50] bci=[-1,1,180] rc=1 vc=538 vn=- li=2 udi=- nc=2 flg=0x1100
n14n     (  1)      l2i                                                                              [     0x3ff69802d60] bci=[-1,1,180] rc=1 vc=538 vn=- li=2 udi=- nc=1
n13n     (  1)        lloadi  <isClassAndDepthFlags>[#319  Shadow +24] [flags 0x603 0x0 ] (cannotOverflow )  [     0x3ff69802d10] bci=[-1,1,180] rc=1 vc=538 vn=- li=2 udi=- nc=1 flg=0x1000
n12n     (  1)          ==>aloadi (in GPR_0034) (X!=0 X>=0 )
n16n     (  2)      iconst 0x10000 (X!=0 X>=0 )                                                      [     0x3ff69802e00] bci=[-1,1,180] rc=2 vc=538 vn=- li=2 udi=- nc=0 flg=0x104
n16n     (  2)    ==>iconst 0x10000 (X!=0 X>=0 )

------------------------------
------------------------------
n22n     (  0)  ificmpne --> block_3 BBStart at n20n ()                                              [     0x3ff69802fe0] bci=[-1,4,180] rc=0 vc=538 vn=- li=2 udi=- nc=2 flg=0x20
n17n     (  0)    iand (in GPR_0038) (X>=0 cannotOverflow )                                          [     0x3ff69802e50] bci=[-1,1,180] rc=0 vc=538 vn=- li=2 udi=- nc=2 flg=0x1100
n14n     (  0)      l2i (in GPR_0038)                                                                [     0x3ff69802d60] bci=[-1,1,180] rc=0 vc=538 vn=- li=2 udi=- nc=1
n13n     (  0)        lloadi  <isClassAndDepthFlags>[#319  Shadow +24] [flags 0x603 0x0 ] (in GPR_0038) (cannotOverflow )  [     0x3ff69802d10] bci=[-1,1,180] rc=0 vc=538 vn=- li=2 udi=- nc=1 flg=0x1000
n12n     (  0)          ==>aloadi (in GPR_0034) (X!=0 X>=0 )
n16n     (  0)      iconst 0x10000 (X!=0 X>=0 )                                                      [     0x3ff69802e00] bci=[-1,1,180] rc=0 vc=538 vn=- li=2 udi=- nc=0 flg=0x104
n16n     (  0)    ==>iconst 0x10000 (X!=0 X>=0 )
------------------------------

[     0x3ff69a00e00]                          LG      GPR_0038, Shadow[<isClassAndDepthFlags>] 24(GPR_0034)
[     0x3ff69a00ed0]                          NILF    GPR_0038,65536
[     0x3ff69a00fe0]                          CFI     GPR_0038,65536
[     0x3ff69a010f0]                          BRC     BNH(0x6), Label L0017

The variables depth, refCountZero, and the memory reference node are updated to capture the above pattern for the l2i node. The updated variables are later used for pattern matching when considering l2i node with a memory reference of depth 2.

The LOAD, AND, CMP instructions generated from this specific pattern are replaced by TM + BRC sequence, which uses the updated memory reference node.

Updated set of tress with TM reduction for l2i node, from an OpenJ9 trace log produced off a JLTF job:

------------------------------
 n22n     (  0)  ificmpne --> block_3 BBStart at n20n ()                                              [     0x3ff8cb66f10] bci=[-1,4,180] rc=0 vc=495 vn=- li=2 udi=- nc=2 flg=0x20
 n17n     (  1)    iand (X>=0 cannotOverflow )                                                        [     0x3ff8cb66d80] bci=[-1,1,180] rc=1 vc=495 vn=- li=2 udi=- nc=2 flg=0x1100
 n14n     (  1)      l2i                                                                              [     0x3ff8cb66c90] bci=[-1,1,180] rc=1 vc=495 vn=- li=2 udi=- nc=1
 n13n     (  1)        lloadi  <isClassAndDepthFlags>[#320  Shadow +24] [flags 0x603 0x0 ] (cannotOverflow )  [     0x3ff8cb66c40] bci=[-1,1,180] rc=1 vc=495 vn=- li=2 udi=- nc=1 flg=0x1000
 n12n     (  1)          ==>aloadi (in GPR_0034) (X!=0 X>=0 )
 n16n     (  2)      iconst 0x10000 (X!=0 X>=0 )                                                      [     0x3ff8cb66d30] bci=[-1,1,180] rc=2 vc=495 vn=- li=2 udi=- nc=0 flg=0x104
 n16n     (  2)    ==>iconst 0x10000 (X!=0 X>=0 )
------------------------------
------------------------------
 n22n     (  0)  ificmpne --> block_3 BBStart at n20n ()                                              [     0x3ff8cb66f10] bci=[-1,4,180] rc=0 vc=495 vn=- li=2 udi=- nc=2 flg=0x20
 n17n     (  0)    iand (X>=0 cannotOverflow )                                                        [     0x3ff8cb66d80] bci=[-1,1,180] rc=0 vc=495 vn=- li=2 udi=- nc=2 flg=0x1100
 n14n     (  0)      l2i                                                                              [     0x3ff8cb66c90] bci=[-1,1,180] rc=0 vc=495 vn=- li=2 udi=- nc=1
 n13n     (  0)        lloadi  <isClassAndDepthFlags>[#320  Shadow +24] [flags 0x603 0x0 ] (cannotOverflow )  [     0x3ff8cb66c40] bci=[-1,1,180] rc=0 vc=495 vn=- li=2 udi=- nc=1 flg=0x1000
 n12n     (  0)          ==>aloadi (in GPR_0034) (X!=0 X>=0 )
 n16n     (  0)      iconst 0x10000 (X!=0 X>=0 )                                                      [     0x3ff8cb66d30] bci=[-1,1,180] rc=0 vc=495 vn=- li=2 udi=- nc=0 flg=0x104
 n16n     (  0)    ==>iconst 0x10000 (X!=0 X>=0 )
------------------------------

 [     0x3ff8ce05580]                          TM       Shadow[<isClassAndDepthFlags>] 29(GPR_0034), 0x01
 [     0x3ff8ce05660]                          BRC     BNP(0xe), Label L0017

Tagging @r30shah for review and verification if more changes may be needed to the function.

[sarwat12]

Tagging @r30shah for review.