[asan] Rewrite Windows/heaprealloc_alloc_zero check to avoid dereference (#156211)

The test currently checks that 1-byte is allocated when malloc(0) is
called, by dereferencing the pointer.
https://github.com/llvm/llvm-project/pull/155943 changed ASan to
consider the dereference to be a heap buffer overflow. This patch
changes the test to check the allocated size is still 1-byte, but not
dereference the pointer.

This aims to fix the breakage reported in
https://github.com/llvm/llvm-project/pull/155943#issuecomment-3239543505

It also enables the test for 64-bit Windows.

GitOrigin-RevId: 6dfd8d0ab46e64d0c30d2b9c60f212b50171fc9d