[builtins][test] XFAIL two SPARC tests

[ro]

Summary

Two SPARC builtins tests are currently FAILing due to codegen bugs:

local-sparcv9/ninja-check-all.err3

Builtins-sparc-sunos :: divtc3_test.c
Builtins-sparcv9-sunos :: compiler_rt_logbl_test.c
Builtins-sparcv9-sunos :: divtc3_test.c

I'd like to XFAIL them to reduce testsuite noise. 

Done as follows, tested on `sparcv9-sun-solaris2.11` and `x86_64-pc-solaris2.11`.
Ok for trunk?

[ro]

Ping? It's been a week now. I don't really know abouth LLVM's testcase xfail policy. Someone to enlighten me?

[MaskRay]

Is rL189780 related? If you can simply fix the issue, you probably don't have to XFAIL the tests...

[ro]

In D64796#1597196, @MaskRay wrote:

Is rL189780 related? If you can simply fix the issue, you probably don't have to XFAIL the tests...

It is related, but the two bugs compiler-rt testing has uncovered are beyond me to fix. They require someone versed in the SPARC
backend to deal with, I fear, that's why I filed the bugs instead of attempting fixes myself.

[ro]

Ping^2? Is it ok to xfail those tests given a fix is far from trivial for me?

[jyknight]

Given the reference to the bug, seems fine to me to commit an xfail here since nobody is actively working to fix this right now.

[ro]

In D64796#1605207, @jyknight wrote:

Given the reference to the bug, seems fine to me to commit an xfail here since nobody is actively working to fix this right now.

Thanks. It seems the SPARC backend is only seeing occasional activity these days, especially for corner cases like (software) long double
support.

test/builtins/Unit/compiler_rt_logbl_test.c

 // RUN: %clang_builtins %s %librt -o %t && %run %t
+//
+// Bug 42496
+// XFAIL: sparcv9-target-arch
+//
 //===-- compiler_rt_logbl_test.c - Test __compiler_rt_logbl ---------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //

test/builtins/Unit/divtc3_test.c

 // RUN: %clang_builtins %s %librt -lm -o %t && %run %t
+//
+// 32-bit: Bug 42493, 64-bit: Bug 42496
+// XFAIL: sparc
+//
 //===-- divtc3_test.c - Test __divtc3 -------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //