RFR: 8351162: Clean up x86 (Macro)Assembler after 32-bit x86 removal

[Vladimir Kozlov]

On Mon, 14 Apr 2025 18:47:56 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> This improvement targets x86 `(Macro)Assembler`. We are mostly cleaning up `LP64` predicated code blocks, and a bit of related code.
> 
> It is enticing to remove all `*ptr` methods, and rename all uses from `*ptr` to `*q`, but that turns out to be very intrusive. That is left for a future RFE, if we ever consider doing it.
> 
> Additional testing:
>  - [x] Linux x86_64 server fastdebug, `all`

I think we need to leave *ptr() methods as they are. We use them for pointers only while *q can be used for integer values.

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

PR Review: https://git.openjdk.org/jdk/pull/24631#pullrequestreview-2769266432