[jdk17u-dev] RFR: 8302838: jabswitch main() should avoid calling exit explicitly

[Goetz Lindenmaier]

I backport this for parity with 17.0.18-oracle

-------------

Commit messages:
 - Backport cba817ae590d1130196d7f9d6e75b8d9b37d384b

Changes: https://git.openjdk.org/jdk17u-dev/pull/4088/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=4088&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8302838
  Stats: 6 lines in 1 file changed: 1 ins; 4 del; 1 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/4088.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/4088/head:pull/4088

PR: https://git.openjdk.org/jdk17u-dev/pull/4088