[serializer] include global proxy in additional context snapshots.

test/cctest/cctest.h

Index: test/cctest/cctest.h
diff --git a/test/cctest/cctest.h b/test/cctest/cctest.h
index 690a8c14cd40cf9b5b9d16117b183300280dce94..c2d4eac846757facb44ad0d606b9c6069455a592 100644
--- a/test/cctest/cctest.h
+++ b/test/cctest/cctest.h
@@ -540,6 +540,11 @@ static inline void ExpectNull(const char* code) {
   CHECK(result->IsNull());
 }
 
+static inline void ExpectException(const char* code) {
+  v8::TryCatch try_catch;
+  CHECK(CompileRun(code).IsEmpty());
+  CHECK(try_catch.HasCaught());
+}
 
 static inline void CheckDoubleEquals(double expected, double actual) {
   const double kEpsilon = 1e-10;