Rename GlobalSynchronization to Locks

Also address some review comments in common_throws relating to
ToStr<InvokeType> and exception detail messages.

Change-Id: Ibf2c0f147689fa236d349bd7f01eed3c2522552b
diff --git a/src/intern_table_test.cc b/src/intern_table_test.cc
index 0d46076..15fa259 100644
--- a/src/intern_table_test.cc
+++ b/src/intern_table_test.cc
@@ -102,7 +102,7 @@
   p.Expect(s0.get());
   p.Expect(s1.get());
   {
-    ReaderMutexLock mu(*GlobalSynchronization::heap_bitmap_lock_);
+    ReaderMutexLock mu(*Locks::heap_bitmap_lock_);
     t.SweepInternTableWeaks(IsMarked, &p);
   }