RFR: 8294696 - BufferedInputStream.transferTo should drain buffer when mark set [v3]

[Markus KARG]

> This PR implements JDK-8294696.

Markus KARG 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 three additional commits since the last revision:

 - Alternative B: Cleanup old buffer to allow GC, then set new same-size buffer to handle buffer poisoning
 - Checking explicitly -1 instead of < 0
 - draining buffer instead of falling back to super.transferTo

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Changes:
  - all: https://git.openjdk.org/jdk/pull/10525/files
  - new: https://git.openjdk.org/jdk/pull/10525/files/26d4f53f..edd9da50

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10525&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10525&range=01-02

  Stats: 54995 lines in 1573 files changed: 35683 ins; 12140 del; 7172 mod
  Patch: https://git.openjdk.org/jdk/pull/10525.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10525/head:pull/10525

PR: https://git.openjdk.org/jdk/pull/10525