RFR: 8247957: remove doclint support for HTML 4 [v3]

[Yoshiki Sato]

> HTML4 is no longer supported in javadoc.
> 
> doclint needs to drop HTML4 support as well.
> The changes consist of:
> * Removing jdk.javadoc.internal.doclint.HtmlVersion and its references.
> * Sorting out supported tags and attributes in HTML5 (including fix incorrect permission of valign in TH, TR, TD, THEAD and TBODY)
> * Modifying test code and expected outputs to be checked in HTML5

Yoshiki Sato has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:

  8257204 and 8256313
  8257204: Remove usage of -Xhtmlversion option from javac
  8256313: JavaCompilation.gmk needs to be updated not to use --doclint-format html5 option

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/893/files
  - new: https://git.openjdk.java.net/jdk/pull/893/files/294b3cce..30db3882

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=893&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=893&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/893.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/893/head:pull/893

PR: https://git.openjdk.java.net/jdk/pull/893