check: move ".log -> .html" conversion in contrib

check: move ".log -> .html" conversion in contrib

That feature has been deprecated in the 1.11.x series, and marked
for removal from the automake core in the 1.12 release.  Here we
implement such removal.

Reference:
  <http://lists.gnu.org/archive/html/automake/2012-01/msg00005.html>

See also commit 'v1.11-650-g20f2ac9'.

* doc/automake.texi, NEWS: Update.
* lib/am/check.am: Don't include 'check-html.am' anymore.
* lib/am/check-html.am: Move ...
* contrib/check-html.am: ... to this, and adjust comments.
* lib/am/Makefile.am (dist_am_DATA): Update.
* contrib/Makefile.am (EXTRA_DIST): Likewise.
* tests/parallel-tests2.test: Adjust.
* tests/parallel-tests-dryrun.test: Remove checks on the
".log -> .html" conversion.
* tests/test-driver-custom-html.test: Remove as obsolete.
* tests/test-driver-custom-no-html.test: Likewise.
* tests/tap-html.test: Likewise.
* tests/list-of-tests.mk: Don't list removed tests anymore.