[clang] [llvm] Finish deleting the le32/le64 targets (PR #98497)

[Andrew Adams via cfe-commits]

abadams wrote:

We were advised to use the pnacl targets at the time the code was written.  We're trying wasm now.

The IR can be generic if you use a subset of C that excludes all the things that vary across the targets you care about. For cases we really can't avoid it (e.g. win32 calling convention stuff for direct3d), we compile that one fragment with a few different target triples.

https://github.com/llvm/llvm-project/pull/98497