Define the NO_SANITIZE_ADDRESS macro in a 'clang-cl /fallback' friendly way

Source/platform/heap/AddressSanitizer.h

Index: Source/platform/heap/AddressSanitizer.h
diff --git a/Source/platform/heap/AddressSanitizer.h b/Source/platform/heap/AddressSanitizer.h
index 6f63ec7c2b416b553f38fedcba9b115cdb4a71b4..0ec6a35dba0d3da1d6beda586d7ba279f22fc54e 100644
--- a/Source/platform/heap/AddressSanitizer.h
+++ b/Source/platform/heap/AddressSanitizer.h
@@ -34,12 +34,20 @@
 // FIXME: Add SyZyASan support?
 #if defined(ADDRESS_SANITIZER)
 #include <sanitizer/asan_interface.h>
-#define NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address))
 #else
 #define ASAN_POISON_MEMORY_REGION(addr, size)   \
     ((void)(addr), (void)(size))
 #define ASAN_UNPOISON_MEMORY_REGION(addr, size) \
     ((void)(addr), (void)(size))
+#endif
+
+// FIXME: Have to handle (ADDRESS_SANITIZER && _WIN32) differently as it uses
+// both Clang (which supports the __attribute__ syntax) and CL (which doesn't)
+// as long as we use "clang-cl /fallback". This shouldn't be needed when Clang
+// handles all the code without falling back to CL.
+#if defined(ADDRESS_SANITIZER) && (!OS(WIN) || COMPILER(CLANG))
+#define NO_SANITIZE_ADDRESS __attribute__((no_sanitize_address))
+#else
 #define NO_SANITIZE_ADDRESS
 #endif