Removed some entries in platform/gtk/TestExpectations for tests expected to fail, but passed.

fast/backgrounds/background-leakage-transforms.html:

- Referenciated in https://webkit.org/b/182765 
- It is fixed because the expectations was updated in r254184 (https://trac.webkit.org/changeset/252598/webkit#file82)
- Actions:
  - Remove it from platform/gtk/TestExpectations
  - Closes https://webkit.org/b/182765


fast/history/page-cache-indexed-closed-db.html

- No referenciated by any bug
- Fixed at some point of this scope: https://trac.webkit.org/log/webkit/?verbose=on&stop_rev=250524&rev=250531. Probably here r250531
- Actions:
  - Add `fast/history/page-cache-indexed-closed-db.html [ Pass ]` in platform/gtk/TestExpectations


fast/text/complex-initial-advance.html

- Referenciated by https://webkit.org/b/115437
- Nikolas Zimmerman commented in the issue: Will update expectations.
- Fixed because the expectations was updated in r250884 (2019-Oct)
- Actions:
  - Remove it from platform/gtk/TestExpectations
  - Closes https://webkit.org/b/115437


imported/blink/fast/text/international/vertical-positioning-with-combining-marks.html

- Referenciated by https://webkit.org/b/151267 - [GTK] Many Layout Tests from imported/blink fail (reftests)
- Fixed by r254190
- Actions:
  - Comment `imported/blink/fast/text/international/vertical-positioning-with-combining-marks.html` "fixed by" in https://webkit.org/b/151267
  - Remove it from platform/gtk/TestExpectations


imported/mozilla/svg/blend-hard-light.svg

- No referenciated by any bug
- Defined as `webkit.org/b/131354 imported/mozilla/svg/blend-hard-light.svg [ ImageOnlyFailure ]` in the global TestExpectations
- Fixed at some point in https://trac.webkit.org/log/webkit/?verbose=on&stop_rev=247348&rev=247350. Probably here: r247350  (2019-Jul)
- Actions:
  - Mark as Pass in platform/gtk/TestExpectations


imported/w3c/web-platform-tests/cors/preflight-failure.htm

- No referenciated by any bug
- Expectations file updated in r253331 (Updated tests with removed console log lines)
- Actions:
  - Add `imported/w3c/web-platform-tests/cors/preflight-failure.htm [ Pass ]` in platform/gtk/TestExpectations
  - Add `imported/w3c/web-platform-tests/cors/preflight-failure.htm [ Pass ]` in platform/wpe/TestExpectations