Automatic update from web-platform-tests [Import Maps] Add tests for rejecting multiple import maps According to the spec after https://github.com/WICG/import-maps/pull/242. Bug: 848607 Change-Id: I21e2d494c75ddf9187d2a8d8b63bc59bccd9beb6 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2618680 Reviewed-by: Domenic Denicola <domenic@chromium.org> Commit-Queue: Hiroshige Hayashizaki <hiroshige@chromium.org> Cr-Commit-Position: refs/heads/master@{#842149} -- wpt-commits: 704b55147c12d54980b16f44346325ebdcd81605 wpt-pr: 27117