The current implementation of os::current_stack_pointer() on windows x64 uses a code stub to read the stack pointer. This means that os::current_stack_pointer() may not be called early on in the bootstrapping. This prevents unhandled oops from being enabled early on.

However, there is an MSVC intrinsic that provides the same functionality without the need to use stubs: _AddressOfReturnAddress()
By changing this implementation, we should be able to call os::current_stack_pointer() early on.