RFR: 8356978: Convert unicode sequences in Java source code to UTF-8 [v3]

[Magnus Ihse Bursie]

> After we converted the source base to be fully UTF-8, we do not need to use unicode sequences (like \u0123) in string literals. Sometimes, that might still make sense, as for control characters, non-breaking space, etc. But for strings that is supposed to be a coherent text in a language that needs non-ASCII parts of Unicode, this is not so. Instead, having the sequences makes the text just harder to read and edit. We have already removed several such sequences before, but some remains.

Magnus Ihse Bursie has updated the pull request incrementally with one additional commit since the last revision:

  Reverting fixes in java.xml and jdk.jdi

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25229/files
  - new: https://git.openjdk.org/jdk/pull/25229/files/37bf474c..5a5d7b7b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25229&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25229&range=01-02

  Stats: 6759 lines in 76 files changed: 0 ins; 0 del; 6759 mod
  Patch: https://git.openjdk.org/jdk/pull/25229.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25229/head:pull/25229

PR: https://git.openjdk.org/jdk/pull/25229