RFR: 8358707: [leyden] Flip AOTCompileEagerly back on

[Aleksey Shipilev]

When upstreaming [JDK-8355003](https://bugs.openjdk.org/browse/JDK-8355003), we introduced `AOTCompileEagerly` flag and defaulted it to disabled, to gate the training data replay. Without AOT code, this causes extra compilations, this is why it is false by default in mainline. But for Leyden, it should remain enabled, since this is the path that loads AOT compiled C2 code. We got this flag as `false` during the mainline->Leyden merge/ports.

Additional testing:
 - [x] Ad-hoc benchmarks
 - [x] Linux x86_64 server fastdebug, `runtime/cds`

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Commit messages:
 - Also move the declaration to match mainline
 - Fix

Changes: https://git.openjdk.org/leyden/pull/76/files
  Webrev: https://webrevs.openjdk.org/?repo=leyden&pr=76&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8358707
  Stats: 6 lines in 1 file changed: 3 ins; 3 del; 0 mod
  Patch: https://git.openjdk.org/leyden/pull/76.diff
  Fetch: git fetch https://git.openjdk.org/leyden.git pull/76/head:pull/76

PR: https://git.openjdk.org/leyden/pull/76