RFR: 8354724: Methods in java.io.Reader to read all characters and all lines [v18]

[Brian Burkhalter]

> Implement the requested methods and add a test thereof.

Brian Burkhalter has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 21 additional commits since the last revision:

 - 8354724: Attempt to further improve verbiage
 - Merge
 - Update src/java.base/share/classes/java/io/Reader.java
   
   8354724: Apply suggested changes for readAllLines.
   
   Co-authored-by: Roger Riggs <Roger.Riggs at Oracle.com>
 - Update src/java.base/share/classes/java/io/Reader.java
   
   8354724: Apply suggested changes for readAllAsString.
   
   Co-authored-by: Roger Riggs <Roger.Riggs at Oracle.com>
 - 8354724: Revert BufferedReader; simplify Reader changes removing overridable self-call; update test
 - 8354724: Fix potential NPE in test
 - 8354724: Fix readAllChars gaffe in Reader returned by Readed.of and account for it in test
 - 8354724: Improve test per reviewer comments
 - 8354724: Add missing toList(), tweak verbiage; update test
 - 8354724: Add Reader.readAllLines; test not yet updated
 - ... and 11 more: https://git.openjdk.org/jdk/compare/b1ab1054...1d811589

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/24728/files
  - new: https://git.openjdk.org/jdk/pull/24728/files/a4cf9224..1d811589

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24728&range=17
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24728&range=16-17

  Stats: 94574 lines in 2581 files changed: 69278 ins; 15222 del; 10074 mod
  Patch: https://git.openjdk.org/jdk/pull/24728.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24728/head:pull/24728

PR: https://git.openjdk.org/jdk/pull/24728