Attempting to pair an `_aligned_malloc` with a regular free causes heap
corruption. Pairing with `_aligned_free` is required instead.
Makes the following libc++ tests pass on Windows:
```
std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t.pass.cpp
std/language.support/support.dynamic/new.delete/new.delete.array/new_align_val_t_nothrow.pass.cpp
std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t.pass.cpp
std/language.support/support.dynamic/new.delete/new.delete.single/new_align_val_t_nothrow.pass.cpp
```
Differential Revision: https://reviews.llvm.org/D28512
llvm-svn: 291743
7ce92f73f2