Add noflip annotation for GSS compiler.

Author: joyzhong

packages/mdc-touch-target/_mixins.scss

@@ -59,6 +59,7 @@
 
   @if $set-width {
     @include mdc-feature-targets($feat-structure) {
+      /* @noflip */
       left: 50%;
       width: $mdc-touch-target-width;
       transform: translate(-50%, -50%);