[PATCH] [lsan] [mips] adding support of lsan for mips64/mips64el arch

[Kumar Sukhani]

I doubt whether its really working.
Even after doing following change 'make check-lsan' is working fine on x86_64

```
TEST(SanitizerLinux, ThreadDescriptorSize) {
   pthread_t tid;
   void *result;
-  ASSERT_EQ(0, pthread_create(&tid, 0, thread_descriptor_size_test_func, 0));
-  ASSERT_EQ(0, pthread_join(tid, &result));
+  ASSERT_EQ(1, pthread_create(&tid, 0, thread_descriptor_size_test_func, 0));
+  ASSERT_EQ(1, pthread_join(tid, &result));
   EXPECT_EQ((uptr)result, ThreadDescriptorSize());
 }

```

http://reviews.llvm.org/D5616