[jdk8u-dev] RFR: 8160974: [TESTBUG] Mark more headful tests with @key headful.

[ktakakuri]

This is a backport of JDK-8160974: [TESTBUG] Mark more headful tests with @key headful.

This patch has already been applied to OracleJDK8.
As noted in the Bug Issue comments, some tests do not exist in 8u.

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Commit messages:
 - Backport e52b963d0cdc49e2048757eae2e4b10bb279f296

Changes: https://git.openjdk.org/jdk8u-dev/pull/383/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=383&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8160974
  Stats: 1065 lines in 533 files changed: 637 ins; 0 del; 428 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/383.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/383/head:pull/383

PR: https://git.openjdk.org/jdk8u-dev/pull/383