<i18n dev> RFR: JDK-8327640: Allow NumberFormat strict parsing [v4]

[Justin Lu]

> Please review this PR and associated [CSR](https://bugs.openjdk.org/browse/JDK-8327703) which introduces strict parsing for NumberFormat.
> 
> The concrete subclasses that will utilize this leniency value are `DecimalFormat` and `CompactNumberFormat`. Strict leniency allows for parsing to be used as an input validation technique for localized formatted numbers. The default leniency mode will remain lenient, and can only be set to strict through an intentional `setLenient(boolean)` method call. Leniency operates differently based off the values returned by `isGroupingUsed()`, `getGroupingSize()`, and `isParseIntegerOnly()`.
> 
> Below is an example of the change, the CSR can be viewed for further detail.
> 
> 
> DecimalFormat fmt = (DecimalFormat) NumberFormat.getNumberInstance(Locale.US);
> fmt.parse("1,,,0,,,00,.23Zabced45");  // returns 1000.23
> fmt.setLenient(false);
> fmt.parse("1,,,0,,,00,.23Zabced45"); // Now throws a ParseException
> fmt.setGroupingSize(2);
> fmt.parse("12,34,567"); // throws ParseException
> fmt.setParseIntegerOnly(true)
> fmt.parse("12,34.56"); // throws ParseException
> fmt.parse("12,34"); // successfully returns the Number 1234
> 
> 
> The associated tests are all localized, and the data is converted properly during runtime.

Justin Lu has updated the pull request incrementally with three additional commits since the last revision:

 - replace protected field for private fields in subclasses for consistency
 - drop Format implNote as well
 - setStrict and isStrict should be optional in NumberFormat
   - specify and throw UOE as default
   - override and implement in dFmt and cmpctNFmt
   parseStrict should be protected, and utilized by subclasses. The public methods should just
   serve as API.

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/18339/files
  - new: https://git.openjdk.org/jdk/pull/18339/files/c09a34dd..4edb4802

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18339&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18339&range=02-03

  Stats: 148 lines in 4 files changed: 87 ins; 24 del; 37 mod
  Patch: https://git.openjdk.org/jdk/pull/18339.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18339/head:pull/18339

PR: https://git.openjdk.org/jdk/pull/18339