Remove tools/clang (this will break things temporarily).

tools/clang/blink_gc_plugin/tests/garbage_collected_mixin.txt

Index: tools/clang/blink_gc_plugin/tests/garbage_collected_mixin.txt
diff --git a/tools/clang/blink_gc_plugin/tests/garbage_collected_mixin.txt b/tools/clang/blink_gc_plugin/tests/garbage_collected_mixin.txt
deleted file mode 100644
index 4051a6a0f73b420a98fcebc1693dd3aa92d8002a..0000000000000000000000000000000000000000
--- a/tools/clang/blink_gc_plugin/tests/garbage_collected_mixin.txt
+++ /dev/null
@@ -1,10 +0,0 @@
-garbage_collected_mixin.cpp:9:1: warning: [blink-gc] Class 'Mixin' has untraced fields that require tracing.
-void Mixin::trace(Visitor* visitor)
-^
-./garbage_collected_mixin.h:16:5: note: [blink-gc] Untraced field 'm_self' declared here:
-    Member<Mixin> m_self;
-    ^
-garbage_collected_mixin.cpp:14:1: warning: [blink-gc] Base class 'Mixin' of derived class 'HeapObject' requires tracing.
-void HeapObject::trace(Visitor* visitor)
-^
-2 warnings generated.