Fix wpt/html/coep/require-corp-about-{blank,srcdoc}.html

 - platform/mac-mac10.13/.../require-corp-about-blank-expected.txt
   is redundant - it's same as the base expectation.
 - platform/mac-mac10.14/.../require-corp-about-blank-expected.txt
   is wrong - the test always fails on the platform (and the failures
   are suppressed by TestExpectations).
 - wpt/html/coep/require-corp-about-blank.html always fails because
   COEP is only effective on secure contexts
   (whatwg/html#4930). Rename it to
   wpt/html/coep/require-corp-about-blank.https.html
 - wpt/html/coep/require-corp-about-srcdoc.html always fails because
   COEP is only effective on secure contexts
   (whatwg/html#4930). Rename it to
   wpt/html/coep/require-corp-about-srcdoc.https.html
 - Remove redundant TestExpectations entries.

Bug: 1086065, 626703
Change-Id: I5573dd4446f482acdde828404e0a88893897ce09
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2274133
Auto-Submit: Yutaka Hirano <[email protected]>
Reviewed-by: Makoto Shimazu <[email protected]>
Commit-Queue: Yutaka Hirano <[email protected]>
Cr-Commit-Position: refs/heads/master@{#783875}

Author: yutakahirano