Remove stray WPT expectation.

set_permission.html was renamed to set_permission.https.html in
https://crrev.com/c/1958825, but for some reason this old expectation file
was not removed.

TBR=smcgruer

Change-Id: Iba55d41cf45c3b15af1d2d0d7bd10e572bbefe06
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1959972Reviewed-by: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Commit-Queue: Raphael Kubo da Costa <raphael.kubo.da.costa@intel.com>
Cr-Commit-Position: refs/heads/master@{#723359}

third_party/blink/web_tests/external/wpt/infrastructure/testdriver/set_permission-expected.txt

-This is a testharness.js-based test.
-FAIL Grant Permission for one realm promise_test: Unhandled rejection with value: object "Error: unimplemented"
-FAIL Deny Permission, omit one realm promise_test: Unhandled rejection with value: object "Error: unimplemented"
-Harness: the test ran to completion.
-