RFR: 8311939: Excessive allocation of Matcher.groups array [v3]

[Cristian Vat]

> Reduces excessive allocation of Matcher.groups array when the original Pattern has no groups or less than 9 groups.
> 
> Original clamping to 10 possibly due to documented behavior from javadoc: 
> "In this class, \1 through \9 are always interpreted as back references, "
> 
> Only with Matcher changes RegExTest.backRefTest fails when backreferences to non-existing groups are present.
> Added a match failure condition in Pattern that fixes failing tests.
> 
> As per existing `java.util.regex.Pattern.BackRef#match`: "// If the referenced group didn't match, neither can this"
> 
> A group that does not exist in the original Pattern can never match so neither can a backref to that group.
> If the group existed in the original Pattern then it would have had space allocated in Matcher.groups for that group index.
> So a group index outside groups array length must never match.

Cristian Vat has updated the pull request incrementally with one additional commit since the last revision:

  remove new line

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Changes:
  - all: https://git.openjdk.org/jdk/pull/14894/files
  - new: https://git.openjdk.org/jdk/pull/14894/files/596eb3db..4c6c3ec0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14894&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14894&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/14894.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14894/head:pull/14894

PR: https://git.openjdk.org/jdk/pull/14894