Add "own" symbols support.

tools/generate-runtime-tests.py

Index: tools/generate-runtime-tests.py
diff --git a/tools/generate-runtime-tests.py b/tools/generate-runtime-tests.py
index 0fb65a5dbab01968f911ca9514d7c5a5edbd1dfb..e9f558fc91afd0a60ddfaeeca537d62e559b37f4 100755
--- a/tools/generate-runtime-tests.py
+++ b/tools/generate-runtime-tests.py
@@ -47,8 +47,8 @@ EXPAND_MACROS = [
 # that the parser doesn't bit-rot. Change the values as needed when you add,
 # remove or change runtime functions, but make sure we don't lose our ability
 # to parse them!
-EXPECTED_FUNCTION_COUNT = 427
-EXPECTED_FUZZABLE_COUNT = 330
+EXPECTED_FUNCTION_COUNT = 428
+EXPECTED_FUZZABLE_COUNT = 331
 EXPECTED_CCTEST_COUNT = 7
 EXPECTED_UNKNOWN_COUNT = 16
 EXPECTED_BUILTINS_COUNT = 809
@@ -226,6 +226,7 @@ CUSTOM_KNOWN_GOOD_INPUT = {
   "CreateBreakIterator": ["'en-US'", "{type: 'string'}", None, None],
   "CreateJSFunctionProxy": [None, "function() {}", None, None, None],
   "CreatePrivateSymbol": ["\"foo\"", None],
+  "CreatePrivateOwnSymbol": ["\"foo\"", None],
   "CreateSymbol": ["\"foo\"", None],
   "DateParseString": [None, "new Array(8)", None],
   "DefineAccessorPropertyUnchecked": [None, None, "function() {}",