[clang] [PowerPC] Fix incorrect store alignment for __builtin_vsx_build_pair() (PR #108606)

[Lei Huang via cfe-commits]

lei137 wrote:

> Will this affect the code that is generated for ‘__vector_quad’ values? There is no direct way to load and store those so they will use pair loads and stores.

Not AFAIK. The change will get the alignment from the type given. The LIT test being updated also have `alloca` and `store` of vector quads.  The alignment for those instructions stayed 64bit.


https://github.com/llvm/llvm-project/pull/108606