[clang] [llvm] [SPIRV] Add support for the `SPV_EXT_long_vector` extension (PR #210279)

[Douglas Yung via llvm-commits]

dyung wrote:

Is there any progress with fixing the test failures from this change? I am seeing 445 test failures on two of my bots:

- https://lab.llvm.org/buildbot/#/builders/174/builds/40360
- https://lab.llvm.org/buildbot/#/builders/202/builds/2351

If we don't have a fix, perhaps we should think about reverting the change?

https://github.com/llvm/llvm-project/pull/210279