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/object_test.cc b/src/object_test.cc
index e44cf64..081be4b 100644
--- a/src/object_test.cc
+++ b/src/object_test.cc
@@ -35,7 +35,7 @@
                     const char* utf8_in,
                     const char* utf16_expected_le,
                     int32_t expected_hash)
-      SHARED_LOCKS_REQUIRED(GlobalSynchronization::mutator_lock_) {
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
     UniquePtr<uint16_t[]> utf16_expected(new uint16_t[length]);
     for (int32_t i = 0; i < length; i++) {
       uint16_t ch = (((utf16_expected_le[i*2 + 0] & 0xff) << 8) |