RFR: 8277353: java/security/MessageDigest/ThreadSafetyTest.java test times out

[Sibabrata Sahoo]

This Test gets timeout during low cpu availability. It is modified to support extended timeout period during JTREG execution.

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Commit messages:
 - 8277353: java/security/MessageDigest/ThreadSafetyTest.java test times out
 - 8277353: java/security/MessageDigest/ThreadSafetyTest.java test times out

Changes: https://git.openjdk.java.net/jdk/pull/6626/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6626&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8277353
  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6626.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6626/head:pull/6626

PR: https://git.openjdk.java.net/jdk/pull/6626