RFR: 8354724: BufferedReader readAllLines and readString methods [v6]

[Brian Burkhalter]

> Implement the requested methods and add a test thereof.

Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:

  8354724: Remove unused import

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/24728/files
  - new: https://git.openjdk.org/jdk/pull/24728/files/8b0b9238..b9424bb4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24728&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24728&range=04-05

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 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