[release/9.0-staging] JIT: fix local assertion prop error for partial local comparisons

[github-actions]

Backport of #112506 to release/9.0-staging

/cc @AndyAyersMS

Customer Impact

• Customer reported
• Found internally

We got a report of incorrect behavior in 9.0 on github: #111352

This is silent bad code and could impact customers unexpectedly.

Regression

• Yes
• No

Introduced by #94741. We enabled more aggressive assertion propagation in the JIT "morph" phase, and one of the new classes of assertions could incorrectly draw inferences from operations on just the low 32 bits of long variables.

For example; if the program had code like

long x = ...;
long y = ...;
if ((int)x == (int)y)
{
     Console.WriteLine($"{x},{y}");
}

Then the JIT would mistakenly optimize the WriteLine to WriteLine($"{x},{x}");

Testing

Verified on a private repo case from the user that opened the issue, and extracted the problematic pattern and added a new test case.

Risk

Low. This optimization was enabled in our mainline in Dec 2023 and has just surfaced now. Also, no SPMI hits for this pattern.

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[AndyAyersMS]

cc @dotnet/jit-contrib @jeffschwMSFT

[jeffschwMSFT]

lgtm. please get a code review. we will take this for consideration in 9.0.x