ART: Enable bugprone-unused-return-value

Enable bugprone-unused-return-value as an error. This is on top of
the compiler warning for attribute((warn_unused)).

Mark the current occurrences (all unique_ptr.release()) with NOLINT
to signal that we know what we're doing.

Bug: 32619234
Bug: 117926937
Test: WITH_TIDY=1 mmma art
Change-Id: I36659722335eef36acfa5845289104257a393874
diff --git a/openjdkjvmti/ti_thread.cc b/openjdkjvmti/ti_thread.cc
index a0e5b5c..33909f7 100644
--- a/openjdkjvmti/ti_thread.cc
+++ b/openjdkjvmti/ti_thread.cc
@@ -812,7 +812,7 @@
     runtime->EndThreadBirth();
     return ERR(INTERNAL);
   }
-  data.release();
+  data.release();  // NOLINT pthreads API.
 
   return ERR(NONE);
 }