Add isfinite() tests

[danbrown-amd]

Resolves #919

[danbrown-amd]

Same data as isinf()/isnan() tests; same code except for the intrinsic invoked. Each filled output slot should be 1 iff the corresponding slots in the other two tests are both 0.

[kmpeng]

My comments suggest slight changes to the scalar/vector tests that make them not completely parallel with isinf and isnan, but I think that's fine since those tests are kind of old

[kmpeng]

Don't think this is the right link

Suggested change

	# Bug https://github.com/llvm/llvm-project/issues/140824
	# Unimplemented https://github.com/llvm/llvm-project/issues/99131

[danbrown-amd]

The bug applies as well, so I've included both lines.

[kmpeng]

That bug was actually mislabeled for isinf and isnan. This was the real bug: llvm/llvm-project#226308, which was fixed. I'm guessing this is the real bug for isfinite too. Can you confirm? If it is, remove the bug comment and leave just the unimplemented one.

Note: I think we're going to run into a different Clang Vulkan bug once the isfinite implementation goes in (same one as isinf/isnan), but let's just update that later when we go to remove the unimplemented xfails.

[danbrown-amd]

Done, though my PR addressing #140824 made those tests pass (for DirectX) as well. That PR is still needed to make the original example work.

[kmpeng]

Edit: You likely need to remove the bug comment from the matrix test, then LGTM

LGTM, will get you another reviewer and merge it in for you once it's approved

Side note: did you want to request commit access to LLVM so you can merge PRs in yourself? You should have enough contributions to request it