RFR: 8263560: Remove needless wrapping with BufferedInputStream [v3]

[Сергей Цыпанов]

> In some cases wrapping of `InputStream` with `BufferedInputStream` is redundant, e.g. in case the wrapped one is `ByteArrayOutputStream` which does not require any buffer having one within.
> 
> Other cases are related to reading either a byte or short `byte[]`: in both cases `BufferedInputStream.fill()` will be called resulting in load of much bigger amount of data (8192 by default) than required.

Сергей Цыпанов has updated the pull request incrementally with one additional commit since the last revision:

  Use InputStream.readNBytes() and fix JLinkNegativeTest

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2992/files
  - new: https://git.openjdk.java.net/jdk/pull/2992/files/12505d05..a016d2ac

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2992&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2992&range=01-02

  Stats: 5 lines in 2 files changed: 2 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2992.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2992/head:pull/2992

PR: https://git.openjdk.java.net/jdk/pull/2992