Bug 4588827 synchronized keyword add/rm compatible

This only addresses the API check part, html output still has "synchronized".

Change-Id: I4df22215480776462b6113ad802d2b46b696a41c
diff --git a/src/com/google/doclava/MethodInfo.java b/src/com/google/doclava/MethodInfo.java
index c0ad628..b2d0839 100644
--- a/src/com/google/doclava/MethodInfo.java
+++ b/src/com/google/doclava/MethodInfo.java
@@ -777,12 +777,16 @@
       consistent = false;
     }
 
+    // see JLS 3 13.4.20 "Adding or deleting a synchronized modifier of a method does not break "
+    // "compatibility with existing binaries."
+    /*
     if (mIsSynchronized != mInfo.mIsSynchronized) {
       Errors.error(Errors.CHANGED_SYNCHRONIZED, mInfo.position(), "Method " + mInfo.qualifiedName()
           + " has changed 'synchronized' qualifier from " + mIsSynchronized + " to "
           + mInfo.mIsSynchronized);
       consistent = false;
     }
+    */
 
     for (ClassInfo exception : thrownExceptions()) {
       if (!mInfo.throwsException(exception)) {