RFR: 8253842: [JVMCI] Allow implicit exception to dispatch to other address in jvmci compilers.

[Yudi Zheng]

This change allows JVMCI compilers to append an entry with flexible dispatch offset to the implicit exception table.

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Commit messages:
 - Allow implicit exception to dispatch to other address in jvmci compilers.

Changes: https://git.openjdk.java.net/jdk/pull/472/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=472&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253842
  Stats: 91 lines in 4 files changed: 89 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/472.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/472/head:pull/472

PR: https://git.openjdk.java.net/jdk/pull/472