[jdk17u-dev] RFR: 8318613: ChoiceFormat patterns are not well tested

[Roland Mesde]

Backporting 8318613: ChoiceFormat patterns are not well tested. The new test checks, both correct and incorrect patterns, the behavior of incorrect patterns that either throw an IllegalArgumentException or discard the incorrect portion, and the case of formatting with an empty pattern (that leads to empty limits and formats). Ran GHA Sanity Checks (1 unrelated test failure - java/lang/ProcessBuilder/Basic.java#id0) and adjusted test (passed). Patch is clean.

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Commit messages:
 - Backport 10427c023a142a24db3c2492977a7233a1afc25d

Changes: https://git.openjdk.org/jdk17u-dev/pull/4117/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=4117&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8318613
  Stats: 153 lines in 1 file changed: 153 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/4117.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/4117/head:pull/4117

PR: https://git.openjdk.org/jdk17u-dev/pull/4117