[NativeAOT-LLVM] Add tracked SSA locals to the first basic block LiveIn set.

[yowl]

This PR adds tracked SSA variables to the Live In set for the first basic block, fixing an assert in release config.

Fixes #2682

[yowl]

cc @dotnet/nativeaot-llvm

Thanks @SingleAccretion for the fix.

[SingleAccretion]

Could you also add a test for this case?

[yowl]

Could you also add a test for this case?

Any idea what that would look like? I tried a few things, but not sure exactly what triggered the error.

[SingleAccretion]

Any idea what that would look like? I tried a few things, but not sure exactly what triggered the error.

It should cause the initial and unused definition of a tracked parameter to become live due to a safe point between it and the first (actual) definition. So, something like:

object func(object a) {
   SafePoint();
   a = new object();
   SafePoint(); // Force 'a' to the shadow stack
   return a;
}

[yowl]

Thanks, that does it.

[SingleAccretion]

LGTM. Thank you!