RFR: JDK-8295859 Update Manual Test Groups

[Bill Huang]

The purpose of this task is to add the difference between -manual jdk_core and jdk_core_manual to the jdk_core_manual test goal. Furthermore, in order to streamline the manual test execution process, a new test group called jdk_core_manual_human has been created for manual tests that demand extra preparation or test input.

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Commit messages:
 - JDK-8295859 Update Manual Test Groups.

Changes: https://git.openjdk.org/jdk/pull/12840/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12840&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295859
  Stats: 24 lines in 1 file changed: 16 ins; 3 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/12840.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12840/head:pull/12840

PR: https://git.openjdk.org/jdk/pull/12840