RFR: 8304017: ProblemList com/sun/jdi/InvokeHangTest.java on windows-x64 in vthread mode

[Daniel D. Daugherty]

Trivial fixes to ProblemList 3 different tests:
[JDK-8304017](https://bugs.openjdk.org/browse/JDK-8304017) ProblemList com/sun/jdi/InvokeHangTest.java on windows-x64 in vthread mode
[JDK-8304018](https://bugs.openjdk.org/browse/JDK-8304018) ProblemList javax/swing/JColorChooser/Test6827032.java on windows-x64
[JDK-8304019](https://bugs.openjdk.org/browse/JDK-8304019) ProblemList java/awt/dnd/MissingDragExitEventTest/MissingDragExitEventTest.java on windows-x64

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Commit messages:
 - 8304019: ProblemList java/awt/dnd/MissingDragExitEventTest/MissingDragExitEventTest.java on windows-x64
 - 8304018: ProblemList javax/swing/JColorChooser/Test6827032.java on windows-x64
 - 8304017: ProblemList com/sun/jdi/InvokeHangTest.java on windows-x64 in vthread mode

Changes: https://git.openjdk.org/jdk/pull/12990/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12990&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8304017
  Stats: 5 lines in 2 files changed: 3 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/12990.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12990/head:pull/12990

PR: https://git.openjdk.org/jdk/pull/12990