JIT: start checking sum of successor likelihoods

[AndyAyersMS]

Add the ability to check that successor edge likelihoods sum to 1.0 Verify that successor edge likelihoods sum to 1.0 for the phases up through and including fgAddInternal.

Fixed a few problems

• importer branch folding needs to update likelihoods
• gdv likelihood needed some adjustments, especially for the multi-guess case
• profile incorporation for OSR methods also needed some fixing. Here we may have inconsistencies so the right answer is not always clear. With this change we now trust the successor edge counts even if they do not sum to the block count.

Contributes to #93020.

Diffs

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Issue Details

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Add the ability to check that uccessor edge likelihoods sum to 1.0 Verify that successor edge likelihoods sum to 1.0 for the phases up through and including fgAddInternal.

Fixed a few problems

• importer branch folding needs to update likelihoods
• gdv likelihood needed some adjustments, especially for the multi-guess case
• profile incorporation for OSR methods also needed some fixing. Here we may have inconsistencies so the right answer is not always clear. With this change we now trust the successor edge counts even if they do not sum to the block count.

Contributes to #93020.

Author:	AndyAyersMS
Assignees:	AndyAyersMS
Labels:	area-CodeGen-coreclr
Milestone:	-

[AndyAyersMS]

@amanasifkhalid PTAL
cc @dotnet/jit-contrib

A few small diffs expected.

[amanasifkhalid]

LGTM, I'll take another look once you've merged from main. Thanks!

[amanasifkhalid]

LGTM, thanks!

[AndyAyersMS]

One runtime failure is #99074, another is (perhaps) #98817
Replays are hitting some sort of infra issue trying to download results from helix?

  Waiting for completion of job 0a0cdc60-4209-4427-8d83-4668d827952c on Windows.10.Amd64.Open (Details: https://helix.dot.net/api/jobs/0a0cdc60-4209-4427-8d83-4668d827952c/details?api-version=2019-06-17 )
  Job 0a0cdc60-4209-4427-8d83-4668d827952c on Windows.10.Amd64.Open is completed with 7 finished work items.
  Downloading result files for job 0a0cdc60-4209-4427-8d83-4668d827952c
D:\a\_work\1\s\.packages\microsoft.dotnet.helix.sdk\9.0.0-beta.24112.1\tools\download-results\DownloadFromResultsContainer.targets(26,5): 
   error : RestApiException`1: The response contained an invalid status code 500 Internal Server Error
   [D:\a\_work\1\s\src\coreclr\scripts\superpmi-replay.proj]

``