[KERNEL32] Add stubs for HeapAlloc and HeapFree

This allows external code linked into kernel32 to link to these functions, which are otherwise defined as macros to RtlAllocateHeap and RtlFreeHeap.
This will be needed for NT6 apis.

dll/win32/kernel32/client/heapmem.c

@@ -1860,5 +1860,26 @@ LocalUnlock(HLOCAL hMem)
     RtlUnlockHeap(BaseHeap);
     return RetVal;
 }
+#undef HeapAlloc
+LPVOID
+WINAPI
+HeapAlloc(
+    _In_ HANDLE hHeap,
+    _In_ DWORD  dwFlags,
+    _In_ SIZE_T dwBytes)
+{
+    return RtlAllocateHeap(hHeap, dwFlags, dwBytes);
+}
+
+#undef HeapFree
+BOOL
+WINAPI
+HeapFree(
+    _In_ HANDLE hHeap,
+    _In_ DWORD dwFlags,
+    _In_ _Frees_ptr_opt_ LPVOID lpMem)
+{
+    return RtlFreeHeap(hHeap, dwFlags, lpMem);
+}
 
 /* EOF */