RFR: 8296190: TestMD5Intrinsics and TestMD5MultiBlockIntrinsics don't test the intrinsics

[Yi-Fan Tsai]

Increase WARMUP_ITERATIONS to get MD5 hash from the intrinsic. The current value is too low and the intrinsic is not executed.

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Commit messages:
 - 8296190: TestMD5Intrinsics and TestMD5MultiBlockIntrinsics don't test the intrinsics

Changes: https://git.openjdk.org/jdk/pull/10954/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10954&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8296190
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/10954.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10954/head:pull/10954

PR: https://git.openjdk.org/jdk/pull/10954