RFR: 8304144: G1: Remove unnecessary is_survivor check in G1ClearCardTableTask

[Y. Srinivas Ramakrishna]

On Tue, 14 Mar 2023 15:02:57 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Simple removing redundant check.
> 
> Test: tier1-6

Reviewed modulo comment above about why I think the assert still makes sense.

-------------

Marked as reviewed by ysr (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/13023#pullrequestreview-1349559870