Check consistency of manual trace and finalization dispatching.

tools/clang/blink_gc_plugin/tests/trace_after_dispatch.txt

Index: tools/clang/blink_gc_plugin/tests/trace_after_dispatch.txt
diff --git a/tools/clang/blink_gc_plugin/tests/trace_after_dispatch.txt b/tools/clang/blink_gc_plugin/tests/trace_after_dispatch.txt
new file mode 100644
index 0000000000000000000000000000000000000000..e076e3424da3e6c0729dacc46db7bc05ce40dc8a
--- /dev/null
+++ b/tools/clang/blink_gc_plugin/tests/trace_after_dispatch.txt
@@ -0,0 +1,13 @@
+trace_after_dispatch.cpp:11:1: warning: [blink-gc] Missing dispatch to class 'D' in manual trace dispatch.
+void A::trace(Visitor* visitor)
+^
+trace_after_dispatch.cpp:30:1: warning: [blink-gc] Base class 'A' of derived class 'B' requires tracing.
+void B::traceAfterDispatch(Visitor* visitor)
+^
+trace_after_dispatch.cpp:36:1: warning: [blink-gc] Class 'C' has untraced fields that require tracing.
+void C::traceAfterDispatch(Visitor* visitor)
+^
+./trace_after_dispatch.h:36:5: note: [blink-gc] Untraced field 'm_a' declared here:
+    Member<A> m_a;
+    ^
+3 warnings generated.