[flang][hlfir] address post-commit comments from D151247 and D151251

Addresses comments not addressed in https://reviews.llvm.org/D151251
and https://reviews.llvm.org/D151247

- Fix typo in comments.
- Update an expected test output to include the fir.allocmem argument.
- Make a more generic type comparisons and cast when fetching value
  back from the AnyValueStack temporary storage.

Differential Revision: https://reviews.llvm.org/D151428