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

[Phil Race]

On Sun, 14 Mar 2021 19:35:25 GMT, Сергей Цыпанов <github.com+10835776+stsypanov at openjdk.org> wrote:

>> 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

2d change is fine.

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Marked as reviewed by prr (Reviewer).

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