RFR: 8378698: Optimize Base64.Encoder#encodeToString [v4]

[Patrick Strawderman]

> Avoid a byte array copy in encodeToString by using JavaLangAccess#uncheckedNewStringWithLatin1Bytes

Patrick Strawderman has updated the pull request incrementally with one additional commit since the last revision:

  Update license for benchmark
  
  Co-authored-by: Chen Liang <liach at openjdk.org>

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Changes:
  - all: https://git.openjdk.org/jdk/pull/29920/files
  - new: https://git.openjdk.org/jdk/pull/29920/files/a2fa6d14..4e82915a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29920&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29920&range=02-03

  Stats: 3 lines in 1 file changed: 0 ins; 2 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/29920.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29920/head:pull/29920

PR: https://git.openjdk.org/jdk/pull/29920