RFR: 8256552: Let ReplayCompiles set UseDebuggerErgo

[Nils Eliasson]

When replaying compiles a lot of unnecessary threads are started. The new excellent UseDebuggerErgo flag is a perfect match for replay.

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Commit messages:
 - ReplayCompiles sets UseDebuggerErgo

Changes: https://git.openjdk.java.net/jdk/pull/1289/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1289&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8256552
  Stats: 4 lines in 1 file changed: 4 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1289.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1289/head:pull/1289

PR: https://git.openjdk.java.net/jdk/pull/1289