Revert of Throw when case mapping result > max string length

src/runtime/runtime-i18n.cc

Index: src/runtime/runtime-i18n.cc
diff --git a/src/runtime/runtime-i18n.cc b/src/runtime/runtime-i18n.cc
index b01190e8ee412786c144cf9dd3b1355c430f1ea2..7d2594cd327fa6db1246110a17083ef7096160c3 100644
--- a/src/runtime/runtime-i18n.cc
+++ b/src/runtime/runtime-i18n.cc
@@ -63,7 +63,6 @@
 
 }  // namespace
 
-// ECMA 402 6.2.3
 RUNTIME_FUNCTION(Runtime_CanonicalizeLanguageTag) {
   HandleScope scope(isolate);
   Factory* factory = isolate->factory();
@@ -74,8 +73,6 @@
   v8::String::Utf8Value locale_id(v8::Utils::ToLocal(locale_id_str));
 
   // Return value which denotes invalid language tag.
-  // TODO(jshin): Can uloc_{for,to}TanguageTag fail even for structually valid
-  // language tags? If not, just add CHECK instead of returning 'invalid-tag'.
   const char* const kInvalidTag = "invalid-tag";
 
   UErrorCode error = U_ZERO_ERROR;
@@ -862,8 +859,8 @@
   // This is not a real loop. It'll be executed only once (no overflow) or
   // twice (overflow).
   for (int i = 0; i < 2; ++i) {
-    ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
-        isolate, result, isolate->factory()->NewRawTwoByteString(dest_length));
+    result =
+        isolate->factory()->NewRawTwoByteString(dest_length).ToHandleChecked();
     DisallowHeapAllocation no_gc;
     String::FlatContent flat = s->GetFlatContent();
     const UChar* src = GetUCharBufferFromFlat(flat, &sap, src_length);