Fix misleading mutex_test.cc comments.

Change-Id: If0ea3c09d61a05fcd2e5bdef31a4f79a07d94a28
diff --git a/src/mutex_test.cc b/src/mutex_test.cc
index 4931551..4220f2b 100644
--- a/src/mutex_test.cc
+++ b/src/mutex_test.cc
@@ -42,7 +42,7 @@
   MutexTester::AssertDepth(mu, 0U);
 }
 
-// GCC doesn't get recursive mutexes, so we have to turn off thread safety analysis.
+// GCC has trouble with our mutex tests, so we have to turn off thread safety analysis.
 static void TryLockUnlockTest() NO_THREAD_SAFETY_ANALYSIS {
   Mutex mu("test mutex");
   MutexTester::AssertDepth(mu, 0U);
@@ -56,7 +56,7 @@
   TryLockUnlockTest();
 }
 
-// GCC doesn't get recursive mutexes, so we have to turn off thread safety analysis.
+// GCC has trouble with our mutex tests, so we have to turn off thread safety analysis.
 static void RecursiveLockUnlockTest() NO_THREAD_SAFETY_ANALYSIS {
   Mutex mu("test mutex");
   MutexTester::AssertDepth(mu, 0U);
@@ -74,7 +74,7 @@
   RecursiveLockUnlockTest();
 }
 
-// GCC doesn't get recursive mutexes, so we have to turn off thread safety analysis.
+// GCC has trouble with our mutex tests, so we have to turn off thread safety analysis.
 static void RecursiveTryLockUnlockTest() NO_THREAD_SAFETY_ANALYSIS {
   Mutex mu("test mutex");
   MutexTester::AssertDepth(mu, 0U);