[jdk8u-dev] RFR: 8298108: Add a regression test for JDK-8297684 [v2]

[Severin Gehwolf]

> Please review this backport of the regression test for a critical fix which we've included with the January CPU update. The fix was https://bugs.openjdk.org/browse/JDK-8280890
> 
> This patch adds an additional regression test which was seen in the wild with JDK 17. The patch isn't clean since the test library in jdk8u is different so needed a bit of a different setup routine for getting the jar with the provider created. Additionally, in jdk 8 the property to add providers is setting `java.ext.dirs=...` over `java.locale.providers=SPI` in later JDKs.
> 
> Testing: The test passes for me on the current dev tree and fails with the fix from JDK-8280890 reverted.
> 
> Thoughts?

Severin Gehwolf has updated the pull request incrementally with one additional commit since the last revision:

  Remove erroneous java.home in ext dirs property

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Changes:
  - all: https://git.openjdk.org/jdk8u-dev/pull/269/files
  - new: https://git.openjdk.org/jdk8u-dev/pull/269/files/2e937ca2..203a9ef6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=269&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=269&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/269.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/269/head:pull/269

PR: https://git.openjdk.org/jdk8u-dev/pull/269