8253375: OSX build fails with Xcode 12.0 (12A7209)

Replace double array with short array in AdapterHandlerLibrary::create_native_wrapper, add parens around ?: in CSystemColors:getColor

Reviewed-by: prr, kbarrett, lucy

src/hotspot/share/runtime/sharedRuntime.cpp

@@ -2856,8 +2856,8 @@ void AdapterHandlerLibrary::create_native_wrapper(const methodHandle& method) {
     BufferBlob*  buf = buffer_blob(); // the temporary code buffer in CodeCache
     if (buf != NULL) {
       CodeBuffer buffer(buf);
-      double locs_buf[20];
-      buffer.insts()->initialize_shared_locs((relocInfo*)locs_buf, sizeof(locs_buf) / sizeof(relocInfo));
+      struct { double data[20]; } locs_buf;
+      buffer.insts()->initialize_shared_locs((relocInfo*)&locs_buf, sizeof(locs_buf) / sizeof(relocInfo));
 #if defined(AARCH64)
       // On AArch64 with ZGC and nmethod entry barriers, we need all oops to be
       // in the constant pool to ensure ordering between the barrier and oops