<Swing Dev> RFR: 8258040: Reenable fixed problemlisted test

[Prasanta Sadhukhan]

javax/swing/JPopupMenu/6675802/bug6675802.java was failing due to JDK-6847157 which has been subseqeuntly fixed, so this test should be removed from problemlist.
Ran several iterations of the test in mach5 which is green. Link in JBS.

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Commit messages:
 - Reenable PL test

Changes: https://git.openjdk.java.net/jdk/pull/1735/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1735&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8258040
  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1735.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1735/head:pull/1735

PR: https://git.openjdk.java.net/jdk/pull/1735