RFR: 1722: Add duration logging for RestRequestCache lock

[Erik Joelsson]

This patch adds additional logging of durations for things that take time. In this case it's measuring how long it takes to get the lock before calling a remote REST API.

-------------

Commit messages:
 - SKARA-1722

Changes: https://git.openjdk.org/skara/pull/1444/files
 Webrev: https://webrevs.openjdk.org/?repo=skara&pr=1444&range=00
  Issue: https://bugs.openjdk.org/browse/SKARA-1722
  Stats: 12 lines in 1 file changed: 6 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/skara/pull/1444.diff
  Fetch: git fetch https://git.openjdk.org/skara pull/1444/head:pull/1444

PR: https://git.openjdk.org/skara/pull/1444