[CFE][Codegen][In-progress] Remove CodeGenFunction::InitTempAlloca()

Sequel patch to https://reviews.llvm.org/D111293.

Remove call to CodeGenFunction::InitTempAlloca() from OpenMP related
codegen part.

Also remove the metadata `!llvm.access.group` from the updated lit
tests.

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D111316