RFR: 8293353: [BACKOUT] G1: Remove redundant is-marking-active checks in C1 barrier

[Kim Barrett]

On Mon, 5 Sep 2022 08:58:33 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Clean revert of [JDK-8289138](https://bugs.openjdk.org/browse/JDK-8289138) to keep CI clean.
> 
> Test: ~2/200 failing rate before the PR and pass after the PR.

Looks good.

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Marked as reviewed by kbarrett (Reviewer).

PR: https://git.openjdk.org/jdk/pull/10159