Full build precommit bots were failing due to mis-alignment of atomics
in hermetic tests. This PR enforces the alignment for the bump allocator
of hermetic test framework.

Fixes https://github.com/llvm/llvm-project/issues/128185.

This patch adds two operators delete that are being generated by clang 15 on rv32 (operator delete(void *mem, std::align_val_t)) and by gcc 13 on intel 64 (operator delete(void *mem, unsigned long)).

This is a part of #97655.

Reverts llvm/llvm-project#98075

bots are broken

This is a part of #97655.

Summary:
Not all platforms support this function or header, but it was being
included by every test. Move it inside of the `ifdef` for the only user,
which is aarch64.

Reverts llvm/llvm-project#95419 and Reland #95358.

This PR is full of temporal fixes. After a discussion with @lntue, it is
better to avoid further changes to the cmake infrastructure for now as a
rework to the cmake utilities will be landed in the future.

`-nostdlib++` is a clang-only flag. Replacing it with `-nostdlib` when
building with gcc.

The death test infrastructure seems to depend on operator new, which
isn't currently supported in our hermetic tests. This patch just
disables the death tests in hermetic mode since they only overlap in the
nan tests.