RFR: 8292640: C2: Remove unused scratch register usages on x86

Fri Aug 19 23:55:31 UTC 2022

On Thu, 18 Aug 2022 22:13:07 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

> (PR is dependent on #9932.)
> 
> Remove redundant scratch register usages in C2 generated code on x86. 
> 
> Stubs put constants in code cache, so they are RIP-relative addressable from generated code. It allows to save on scratch registers when accessing constants.  
> 
> Testing: hs-tier1 - hs-tier4

Good.

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Marked as reviewed by kvn (Reviewer).

PR: https://git.openjdk.org/jdk/pull/9933