Integrated: Clean up CondCardMark code: remove excess barriers, enable it by default

[Aleksey Shipilev]

On Wed, 31 Mar 2021 13:34:38 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> The `StoreLoad`, `StoreStore` barriers in that code are only needed for CMS, and does not relate to Shenandoah. Also, `UseCondCardMark` is a recommended option for most machines today, and therefore we better just enable it ergonomically.
> 
> Additional testing:
>  - [x] hotspot_gc_shenandoah, x86_64, {fastdebug,release}

This pull request has now been integrated.

Changeset: d6b1c3f0
Author:    Aleksey Shipilev <shade at openjdk.org>
URL:       https://git.openjdk.java.net/shenandoah/commit/d6b1c3f0
Stats:     35 lines in 6 files changed: 3 ins; 30 del; 2 mod

Clean up CondCardMark code: remove excess barriers, enable it by default

Reviewed-by: zgu

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PR: https://git.openjdk.java.net/shenandoah/pull/26