RFR: 8150564: Migrate useful ExtendedRobot methods into awt.Robot [v21]

[Alisen Chung]

> Some useful methods in ExtendedRobot should be migrated into Robot itself so that ExtendedRobot can be removed in the future. The tests using ExtendedRobot for these migrated methods are changed to use only Robot (removing unnecessary building of ExtendedRobot).

Alisen Chung has updated the pull request incrementally with one additional commit since the last revision:

  remove /lib/client/ from tests with ER removed

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Changes:
  - all: https://git.openjdk.org/jdk/pull/22044/files
  - new: https://git.openjdk.org/jdk/pull/22044/files/9aa82019..8347d2fb

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22044&range=20
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22044&range=19-20

  Stats: 156 lines in 156 files changed: 0 ins; 2 del; 154 mod
  Patch: https://git.openjdk.org/jdk/pull/22044.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22044/head:pull/22044

PR: https://git.openjdk.org/jdk/pull/22044