remove unnecessary synchronized

Author: keithl-stripe

src/main/java/com/google/devtools/build/lib/query2/query/output/StreamedProtoOutputFormatter.java

@@ -89,7 +89,7 @@ private WrappedIOException(IOException cause) {
     }
 
     @Override
-    public synchronized IOException getCause() {
+    public IOException getCause() {
       return (IOException) super.getCause();
     }
   }
@@ -100,7 +100,7 @@ private WrappedInterruptedException(InterruptedException cause) {
     }
 
     @Override
-    public synchronized InterruptedException getCause() {
+    public InterruptedException getCause() {
       return (InterruptedException) super.getCause();
     }
   }