RFR: 8234239: [TEST_BUG] Reenable few ignored web tests

[Arun Joseph]

The following tests can be reenabled:

CookieManager.testPutOverwriteExpired
CookieManager.testPutPurgeDomainAfterExpiry
CookieManager.testPutPurgeCookiesGlobally2
CookieManager.testPutPurgeCookiesGlobally3
CookieManager.testPutPurgeCookiesGloballyAfterExpiry
CallbackTest.testCustomPopup
CallbackTest.testDefaultPopup
LeakTest.testGarbageCollectability
LeakTest.testOleg
MiscellaneousTest.testRT30835

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Commits:
 - f2f121d9: 8234239: Reenable few ignored web tests

Changes: https://git.openjdk.java.net/jfx/pull/42/files
 Webrev: https://webrevs.openjdk.java.net/jfx/42/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8234239
  Stats: 20 lines in 4 files changed: 0 ins; 20 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx/pull/42.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/42/head:pull/42

PR: https://git.openjdk.java.net/jfx/pull/42