RFR: JDK-8305100 [REDO] Clean up JavadocTokenizer

[Jim Laskey]

Previous work had cleaned up the JavacTokenizer, but left JavadocTokenizer alone, mostly due to its perplexing state. This is follow up work to simplify the JavadocTokenizer.

Redo changes:

1. Needed to check for end of data after @deprecated
2. Position of newline in offset map was incorrect (out by one).
3. Skip whitespace after first line (put offsets out by one).

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Commit messages:
 - Correct position for end of line
 - Tweaks to get tests running
 - Handle line terminators.
 - Clean up end of comment detection
 - Skip whitespace before @deprecated
 - Clean up JavadocTokenizer
 - Merge branch 'master' into 8305100
 - Clean up JavadocTokenizer

Changes: https://git.openjdk.org/jdk/pull/13265/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13265&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8305100
  Stats: 416 lines in 4 files changed: 167 ins; 159 del; 90 mod
  Patch: https://git.openjdk.org/jdk/pull/13265.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13265/head:pull/13265

PR: https://git.openjdk.org/jdk/pull/13265