Update Blink GC plugin to reflect that Oilpan is now always enabled.

tools/clang/blink_gc_plugin/tests/raw_ptr_to_gc_managed_class_error.txt

Index: tools/clang/blink_gc_plugin/tests/raw_ptr_to_gc_managed_class_error.txt
diff --git a/tools/clang/blink_gc_plugin/tests/raw_ptr_to_gc_managed_class_error.txt b/tools/clang/blink_gc_plugin/tests/raw_ptr_to_gc_managed_class_error.txt
index be92ee382264a2980bfbc098a4de778247b751b8..c21c8172762fbae001c5eafee8f02b706aef5ec6 100644
--- a/tools/clang/blink_gc_plugin/tests/raw_ptr_to_gc_managed_class_error.txt
+++ b/tools/clang/blink_gc_plugin/tests/raw_ptr_to_gc_managed_class_error.txt
@@ -2,19 +2,16 @@ In file included from raw_ptr_to_gc_managed_class_error.cpp:5:
 ./raw_ptr_to_gc_managed_class_error.h:14:1: error: [blink-gc] Class 'PartObject' contains invalid fields.
 class PartObject {
 ^
-./raw_ptr_to_gc_managed_class_error.h:19:5: note: [blink-gc] Raw pointer field 'm_obj' to a GC managed class declared here:
-    RawPtr<HeapObject> m_obj;
-    ^
-./raw_ptr_to_gc_managed_class_error.h:20:5: note: [blink-gc] Raw pointer field 'm_rawObj' to a GC managed class declared here:
+./raw_ptr_to_gc_managed_class_error.h:19:5: note: [blink-gc] Raw pointer field 'm_rawObj' to a GC managed class declared here:
     HeapObject* m_rawObj;
     ^
-./raw_ptr_to_gc_managed_class_error.h:21:5: note: [blink-gc] Reference pointer field 'm_refObj' to a GC managed class declared here:
+./raw_ptr_to_gc_managed_class_error.h:20:5: note: [blink-gc] Reference pointer field 'm_refObj' to a GC managed class declared here:
     HeapObject& m_refObj;
     ^
-./raw_ptr_to_gc_managed_class_error.h:24:1: error: [blink-gc] Class 'HeapObject' contains invalid fields.
+./raw_ptr_to_gc_managed_class_error.h:23:1: error: [blink-gc] Class 'HeapObject' contains invalid fields.
 class HeapObject : public GarbageCollected<HeapObject> {
 ^
-./raw_ptr_to_gc_managed_class_error.h:29:5: note: [blink-gc] Raw pointer field 'm_objs' to a GC managed class declared here:
+./raw_ptr_to_gc_managed_class_error.h:28:5: note: [blink-gc] Raw pointer field 'm_objs' to a GC managed class declared here:
     HeapVector<HeapObject*> m_objs;
     ^
 2 errors generated.