RFR: 8339726: Remove pausing code (used for testing) from AbstractPrimaryTimer

[John Hendrikx]

This PR removes the pausing logic from AbstractPrimaryTimer.  The test that is using it wasn't actually testing anything in AbstractPrimaryTimer itself, and no other code needs this pausing code.

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Commit messages:
 - Remove unused code

Changes: https://git.openjdk.org/jfx/pull/1558/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1558&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8339726
  Stats: 135 lines in 4 files changed: 0 ins; 134 del; 1 mod
  Patch: https://git.openjdk.org/jfx/pull/1558.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1558/head:pull/1558

PR: https://git.openjdk.org/jfx/pull/1558