[clang][bytecode][test] Test elem size against target wchar (#218837)
I *think* this is the problem here. I thought since I'm not specifying a
target triple, the host triple would always be used.
I've locally checked that elemSize() returns the correct value when
changing the target triple and that works.
The previous approach caused problems on some builders, see
https://github.com/llvm/llvm-project/pull/218707#issuecomment-5417327986
https://github.com/llvm/llvm-project/pull/216736#issuecomment-5419450306