[libcxx] [test] Fix mismatches between aligned operator new and std::free

The XFAIL comments about VCRuntime not providing aligned operator new
are outdated; these days VCRuntime does provide them.

However, the tests used to fail on Windows, as the pointers allocated
with an aligned operator new (which is implemented with _aligned_malloc
on Windows) can't be freed using std::free() on Windows (but they need
to be freed with the corresponding function _aligned_free instead).

Instead override the aligned operator new to return a dummy suitably
aligned pointer instead, like other tests that override aligned operator
new.

Also override `operator delete[]` instead of plain `operator delete`
in the array testcase; the fallback from `operator delete[]` to
user defined `operator delete` doesn't work in all DLL build
configurations on Windows.

Also expand the TEST_NOEXCEPT macros, as these tests only are built
in C++17 mode.

By providing the aligned operator new within the tests, this also makes
these test cases pass when testing back deployment on macOS 10.9.

Differential Revision: https://reviews.llvm.org/D105962