RFR: 8208377: Soft hyphens render if not using TextLayout [v3]

[Daniel Gredler]

> Soft hyphens should never render, regardless of the rendering path used internally.
> 
> This PR does not expand the categorization of "complex" characters in `FontUtilities` in order to force the use of `TextLayout` rendering code paths (as was discussed in JBS).
> 
> Instead, it takes the existing (limited) format-category checks in `sun.font.CMap` (a TrueType font helper class), expands it to a more general / complete default-ignorable check (`FontUtilities.isDefaultIgnorable(int)`), and then moves these checks out of `CMap` and up a level into the `CharToGlyphMapper` classes themselves.
> 
> The Type1 and TTF glyph mappers have been updated, but the macOS glyph mapper has not been updated.

Daniel Gredler has updated the pull request incrementally with one additional commit since the last revision:

  Add more info about test fonts and default-ignorable chars

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22670/files
  - new: https://git.openjdk.org/jdk/pull/22670/files/e0d7f8c4..f7a89cff

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22670&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22670&range=01-02

  Stats: 109 lines in 2 files changed: 104 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/22670.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22670/head:pull/22670

PR: https://git.openjdk.org/jdk/pull/22670