Fix correctness issue in regr_r2

[8dukongjian]

Description

Fix regr_r2 result incorrect. There are two special cases:

1. m2X() = 0, then result should be NULL
2. m2X() != 0 and m2Y() = 0, then result shoule be 1.

Found by facebookincubator/velox#9522

Release Notes

Please follow release notes guidelines and fill in the release notes below.

== RELEASE NOTES ==

General Changes
* Fix regr_r2 result incorrect.

[mbasmanova]

@8dukongjian Thank you for the fix.

CC @tdcmeehan

[mbasmanova]

@8dukongjian Would you update comment message to follow the guidelines?

[8dukongjian]

@8dukongjian Would you update comment message to follow the guidelines?

Thanks, updated.

[mbasmanova]

@8dukongjian Thank you for adding details to the commit message. There is some broken English in the title. Would you update as well? Thanks.

Fix regr_r2 result incorrect

Fix correctness issue in regr_r2

[mbasmanova]

CC: @steveburnett

[steveburnett]

Maybe the following changes to the release note entry:

== RELEASE NOTES ==

General Changes
* Fix correctness issue in regr_r2 :pr:`22611`

@mbasmanova, is there anything else I can help with here?

[mbasmanova]

@8dukongjian Please, help fix commit message here: https://github.com/prestodb/presto/pull/22611/commits

[mbasmanova]

@steveburnett Steve, thank you for looking. Wanted to FYI you because this is a user-visible change in behavior and requires an RN.

[tdcmeehan]

Thanks for the fix @8dukongjian. @wanglinsong can we add this to 0.287?

[8dukongjian]

@8dukongjian Thank you for adding details to the commit message. There is some broken English in the title. Would you update as well? Thanks.

Fix regr_r2 result incorrect

Fix correctness issue in regr_r2

@mbasmanova

Thank you for your comments. Sorry, I was too busy recently and forgot to fix it.

[wanglinsong]

Thanks for the fix @8dukongjian. @wanglinsong can we add this to 0.287?

I cherry-picked it into the release-0.287 branch.