RFR: 8304745: Lazily initialize byte[] in java.io.BufferedInputStream

[Sergey Tsypanov]

By default `BufferedInputStream` is constructed with internal buffer with capacity 8192. In some cases this buffer is never used, e.g. when we call `IS.readNBytes()` or `IS.readAllBytes()` (relying on `BIS.read1()`) or when `BufferedInputStream` is cascaded.

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

Commit messages:
 - 8304745: Polishing
 - 8304745: Revert JavaDoc change
 - 8304745: Adjust JavaDoc
 - 8304745: Preserve behaviour of subclasses
 - 8304745: Rework existing solution
 - 8304745: Fix test
 - 8304745: Fix build
 - 8304745: Lazily initialize byte[] in j.i.BufferedInputStream
 - 8304745: Lazily initialize byte[] in j.i.BufferedInputStream

Changes: https://git.openjdk.org/jdk/pull/13150/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13150&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8304745
  Stats: 19 lines in 1 file changed: 10 ins; 1 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/13150.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13150/head:pull/13150

PR: https://git.openjdk.org/jdk/pull/13150