x86: Sign-extend 32-bit immediates for 64-bit SBB instructions

[Sleigh-InSPECtor]

The 64-bit immediate form of the SBB (Integer Subtraction With Borrow) instruction, uses the wrong field variant for the immediate, causing it to be zero-extended instead of sign-extended.

e.g.:

4f1dffffffff "SBB RAX,-0x1"

• Hardware Reference (AMD CPU): { RAX=0x1, CF=1, SF=0 }
• x86:LE:64:default (Existing): "SBB RAX,0xffffffff" { RAX=0xffffffff00000001, CF=1, SF=1 }
• x86:LE:64:default (This patch): "SBB RAX,-0x1" { RAX=0x1, CF=1, SF=0 }