RFR: 8319204: G1: Change G1CMTask::_termination_time_ms to wallclock time

[Thomas Schatzl]

On Wed, 1 Nov 2023 09:27:41 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Simple switching from thread-cpu to wall-clock time for termination duration metric.

lgtm.

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Marked as reviewed by tschatzl (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/16446#pullrequestreview-1717731348