RFR: 8136895: Writer not closed with disk full error, file resource leaked [v4]

[Brian Burkhalter]

> In`StreamEncoder::implClose`, move `flushLeftoverChar()` inside the `try` block and the closing of the underlying stream inside the `finally` block.

Brian Burkhalter 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:

 - 8136895: Simplify change to implClose()
 - Merge
 - 8136895: Tweak to StreamEncoder::implCose
 - 8136895: Small improvements to StreamEncoderClose test
 - 8136895: Trivial formatting corrections in tests
 - 8136895: Do not swallow exceptions in StreamEncoder::implFlush; add test for OutputStreamWriter; rename test for Channels::newWriter"
 - 8136895: Writer not closed with disk full error, file resource leaked

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Changes:
  - all: https://git.openjdk.org/jdk/pull/13503/files
  - new: https://git.openjdk.org/jdk/pull/13503/files/4c8ab6df..d1965996

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=13503&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=13503&range=02-03

  Stats: 419758 lines in 6343 files changed: 267956 ins; 107764 del; 44038 mod
  Patch: https://git.openjdk.org/jdk/pull/13503.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13503/head:pull/13503

PR: https://git.openjdk.org/jdk/pull/13503