RFR: 8049347: HTMLDocument throws NPE for Block Tag

[Prasanta Sadhukhan]

Trying to iterate for HEAD HTML tag or for any other "Block" Tag results in NPE due to some spurious unhandled code which just return NULL.
Removing the code solves this problem and also does not cause any regression in clientlibs test.

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Commit messages:
 - 8049347: HTMLDocument throws NPE for Block Tag
 - Merge branch 'master' of github.com:prsadhuk/jdk
 - Merge remote-tracking branch 'upstream/master'
 - Merge remote-tracking branch 'upstream/master'
 - Revert "Fix"
 - Fix

Changes: https://git.openjdk.org/jdk/pull/14466/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14466&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8049347
  Stats: 43 lines in 2 files changed: 39 ins; 4 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/14466.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14466/head:pull/14466

PR: https://git.openjdk.org/jdk/pull/14466