[blink][wpt] Add more module evaluation order tests

Add tests for upcoming microtask checkpoint fixes and top-level-await
for modules. The added test cover in more detail the following items:
- onload events
- onerror events
- queueMicrotask

drive-by-fix: Check for onunhandledrejection

Bug: 1022182, 1096455c, 1114034, v8:9344
Change-Id: Ieaa7691bf44e2758ed873ca53bcc6852812dd723
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2346251


Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Dominic Farolino <dom@chromium.org>
Reviewed-by: Hiroshige Hayashizaki <hiroshige@chromium.org>
Cr-Commit-Position: refs/heads/master@{#798126}