Use a getter instead of accessing a field on JCInstance

#1106

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=313258773

core/src/main/java/com/google/errorprone/refaster/ExpressionTemplate.java

@@ -282,7 +282,7 @@ private static int getPrecedence(JCTree leaf, Context context) {
       return (typeCast.expr == leaf) ? TreeInfo.prefixPrec : TreeInfo.noPrec;
     } else if (parent instanceof JCInstanceOf) {
       JCInstanceOf instanceOf = (JCInstanceOf) parent;
-      return TreeInfo.ordPrec + ((instanceOf.clazz == leaf) ? 1 : 0);
+      return TreeInfo.ordPrec + ((instanceOf.getType() == leaf) ? 1 : 0);
     } else if (parent instanceof JCArrayAccess) {
       JCArrayAccess arrayAccess = (JCArrayAccess) parent;
       return (arrayAccess.indexed == leaf) ? TreeInfo.postfixPrec : TreeInfo.noPrec;