RFR: 8292564: x86: Remove redundant casts in Assembler usages

[Vladimir Ivanov]

On Wed, 17 Aug 2022 19:29:18 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

> Clean up Assembler API and remove redundant at use sites.
>  
> They are not needed anymore because implicit casts between Register and integrals are forbidden now.
> 
> Some of the casts are turned into `static_cast`s to assert that constants are small enough to fit into 32-bit immediate.
> 
> Testing: hs-tier1 - hs-tier4

Good catch, Aleksey. I intended to use `checked_cast`, but misremembered the name. Fixed.

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PR: https://git.openjdk.org/jdk/pull/9909