[WPE] Enable most wpt html tests.

[WPE] Enable most wpt html tests.
https://bugs.webkit.org/show_bug.cgi?id=180650

Unreviewed test gardening.

* platform/wpe/TestExpectations:
* platform/wpe/imported/w3c/web-platform-tests/html/semantics/interactive-elements/the-dialog-element/dialog-showModal-expected.txt:
  Added: same as GTK; whitespace-only difference with the generic expectation file.
* platform/wpe/imported/w3c/web-platform-tests/html/semantics/selectors/pseudo-classes/inrange-outofrange-expected.txt:
  Added: whitespace-only difference with the generic expectation file.
* platform/wpe/imported/w3c/web-platform-tests/html/webappapis/system-state-and-capabilities/the-navigator-object/navigator-pluginarray-expected.txt:
  Added: some subtests pass because the plugin array does not contain any
  plugins on WPE, and issues with the actual elements of the array can
  not be detected.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@225744 268f45cc-cd09-0410-ab3c-d52691b4dbfc