RFR: JDK-8290126: Add a check in JavadocTester for "javadoc should not crash" [v4]

[Jonathan Gibbons]

> Please review a simple update to `JavadocTester` to provide a default-on check that no stack traces were written to the STDERR stream.
> 
> There are also some minor cleanup edits suggested by the IDE.

Jonathan Gibbons 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 four additional commits since the last revision:

 - Merge remote-tracking branch 'upstream/master' into 8290126.javadoctester-checkCrash
 - revert (defer) improvement of TagletManager error message; fix TestTFMBuilder.java
 - Respond to review feedback; add new test
 - JDK-8290126: Add a check in JavadocTester for "javadoc should not crash"

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/9458/files
  - new: https://git.openjdk.org/jdk/pull/9458/files/9d4859f1..0d461e3f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9458&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9458&range=02-03

  Stats: 22521 lines in 849 files changed: 13796 ins; 5768 del; 2957 mod
  Patch: https://git.openjdk.org/jdk/pull/9458.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9458/head:pull/9458

PR: https://git.openjdk.org/jdk/pull/9458