[jdk17] RFR: 8256919: BCEL: Utility.encode forget to close

[Joe Wang]

Fix a regression caused by the previous BCEL update. The issue was fixed in the current BCEL repo with a reversal of the previous code, adding back "gos.close();". Note however, doing so will result in a warning: [try] explicit call to close() on an auto-closeable resource. This fix calls finish() instead.

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Commit messages:
 - 8256919: BCEL: Utility.encode forget to close

Changes: https://git.openjdk.java.net/jdk17/pull/141/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk17&pr=141&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8256919
  Stats: 72 lines in 2 files changed: 72 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk17/pull/141.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk17 pull/141/head:pull/141

PR: https://git.openjdk.java.net/jdk17/pull/141