RFR: 8268725: jshell does not support the --enable-native-access option

[Jan Lahoda]

Adding `--enable-native-access` option to JShell. Set as a parameter to the remote agent (`--enable-native-access=ALL-UNNAMED`), but not the compiler, as the compiler does not have this option.

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Commit messages:
 - 8268725: jshell does not support the --enable-native-access option

Changes: https://git.openjdk.java.net/jdk/pull/4810/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4810&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8268725
  Stats: 69 lines in 2 files changed: 69 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4810.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4810/head:pull/4810

PR: https://git.openjdk.java.net/jdk/pull/4810