[ES6 modules] Update ModuleScript::IsErrored to match latest spec.

This CL updates ModuleScript::IsErrored so that it would also consider
its record's [[Status]].

This behavior change will be tested in
wpt/html/semantics/scripting-1/the-script-element/module/evaluation-error-*.html
once we update ModuleTreeLinker to latest #internal-module-script-graph-fetching
procedure

Bug: 594639, 727299, https://github.com/whatwg/html/pull/2674 , https://github.com/tc39/ecma262/pull/916
Change-Id: I575001a44ca1cc2ad5c9208c93c0b628a09086dd
Reviewed-on: https://chromium-review.googlesource.com/558825
Commit-Queue: Kouhei Ueno <kouhei@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#483945}
3 files changed