message: float16 related fails in fail_db (Gen)
diff: % LLVM bugs in released versions, that we have to workaround by applying patches (see llvm_patches
  % folder). The recommended way to build LLVM on Unix is to use "alloy.py".
  %
  +./tests/shuffle2-12.ispc runfail genx64 genx-x8 TGLLP Linux LLVM 12.0 clang++12.0 spv *
  +./tests/shuffle2-12.ispc runfail genx64 genx-x8 unspec Linux LLVM 12.0 clang++12.0 spv *
  +./tests/shuffle2-12.ispc runfail genx64 genx-x16 TGLLP Linux LLVM 12.0 clang++12.0 spv *
  +./tests/shuffle2-12.ispc runfail genx64 genx-x16 unspec Linux LLVM 12.0 clang++12.0 spv *
  +.\tests\shuffle2-12.ispc runfail genx64 genx-x8 unspec Windows LLVM 12.0 cl spv *
  +.\tests\shuffle2-12.ispc runfail genx64 genx-x16 unspec Windows LLVM 12.0 cl spv *
  