RFR: JDK-8286338: suppress warnings about bad @author tags when author info is not generated.

[Jonathan Gibbons]

Please review a simple small change to `TagletManager`, to not report warnings about bad use of tags (such as `@author` and `@version`) when command-line options have not been given to enable the use of the tags in the output (i.e. the `-author` and the dreadfully-named `-version` option.)

The change is more pragmatic than anything else.  There are lots of "bad" uses of `@author` in JDK API documentation, on methods. The alternative would be to permit the tag anywhere, but that would be both a spec change and work to implement the change that we're not really interest in, since the tag is now somewhat deprecated.

Two existing tests are updated, to test the handling of "bad" tags, with and without the enabling option.

Another test has some very (very) old unused lines deleted. If today was Thursday, I'd call it Throwback Thursday. These lines predate the `JavadocTester` conversion.

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Commit messages:
 - JDK-8286338: suppress warnings about bad @author tags when author info is not generated.

Changes: https://git.openjdk.java.net/jdk/pull/8583/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8583&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8286338
  Stats: 99 lines in 4 files changed: 86 ins; 10 del; 3 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8583.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8583/head:pull/8583

PR: https://git.openjdk.java.net/jdk/pull/8583