RFR: 8300979: Lazily initialize (byte, char)arr in java.io.DataInputStream [v5]

[Per Minborg]

> This PR proposed to lazily initialize the scratch arrays only if/when needed.

Per Minborg 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 seven additional commits since the last revision:

 - Merge branch 'master' into dis-lazy
 - Use zero-lenght arrays rather than null
 - Merge branch 'dis-lazy' of https://github.com/minborg/jdk into dis-lazy
 - Update src/java.base/share/classes/java/io/DataInputStream.java
   
   Co-authored-by: Eirik Bjorsnos <eirbjo at gmail.com>
 - Merge branch 'master' into dis-lazy
 - Remove redundant initilizers
 - Lazily initialize (byte, char)arr in java.io.DataInputStream

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/13121/files
  - new: https://git.openjdk.org/jdk/pull/13121/files/ca165dfa..3b1257cc

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13121&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13121&range=03-04

  Stats: 12655 lines in 339 files changed: 4774 ins; 5523 del; 2358 mod
  Patch: https://git.openjdk.org/jdk/pull/13121.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13121/head:pull/13121

PR: https://git.openjdk.org/jdk/pull/13121