Fix TracingServiceImplTest.CommitToForbiddenBufferIsDiscarded on debug.

Test tries to verify an error condition that triggers a DCHECK in debug
builds. Disable it on debug builds.

Change-Id: Ic56b073323087f2271f4500810a3ee439704138b
diff --git a/src/tracing/core/service_impl_unittest.cc b/src/tracing/core/service_impl_unittest.cc
index e941e82..9b50bda 100644
--- a/src/tracing/core/service_impl_unittest.cc
+++ b/src/tracing/core/service_impl_unittest.cc
@@ -985,6 +985,7 @@
   EXPECT_EQ(std::set<BufferID>(), GetAllowedTargetBuffers(producer2_id));
 }
 
+#if !PERFETTO_DCHECK_IS_ON()
 TEST_F(TracingServiceImplTest, CommitToForbiddenBufferIsDiscarded) {
   std::unique_ptr<MockConsumer> consumer = CreateMockConsumer();
   consumer->Connect(svc.get());
@@ -1055,5 +1056,6 @@
   consumer->FreeBuffers();
   EXPECT_EQ(std::set<BufferID>(), GetAllowedTargetBuffers(producer_id));
 }
+#endif  // !PERFETTO_DCHECK_IS_ON()
 
 }  // namespace perfetto