RFR: JDK-8154011: Make TraceDeoptimization a diagnostic flag

[Tobias Holenstein]

Make TraceDeoptimization available in a product build.

I checked that performance is not affected on Aurora.

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Commit messages:
 - JDK-8154011: Make TraceDeoptimization a diagnostic flag

Changes: https://git.openjdk.java.net/jdk/pull/6703/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6703&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8154011
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6703.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6703/head:pull/6703

PR: https://git.openjdk.java.net/jdk/pull/6703