[ES6 modules] Remove usage of ModuleInstantiationState outside ModuleTreeLinker

The spec concept "module script's state" is removed from latest HTML spec.
Remove its usage outside ModuleTreeLinker.

Bonus: Introduce pretty-printer of ModuleScript.

Bug: 594639, 727299, https://github.com/whatwg/html/pull/2674
Change-Id: Ic01d729d4c2bfa546da9138e7a8248b997060c87
Reviewed-on: https://chromium-review.googlesource.com/558567
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Kouhei Ueno <kouhei@chromium.org>
Cr-Commit-Position: refs/heads/master@{#483930}
6 files changed