meta: move all ISLE-related generated code to `cranelift-codegen-meta` (

#10352)

* meta: move all ISLE-related generated code to `cranelift-codegen-meta`

Previously, the new `cranelift-assembler-x64` crate would generate the
assembler Rust code, the ISLE integration code, and the ISLE's
accompanying Rust macro all in the same crate. Because these last two
files were generated in the assembler's `OUT_DIR`, they caused issues
for deterministic builds that expect those files in
`cranelift-codegen`'s `OUT_DIR` (see #10348). This change fixes that by
moving all of the assembler's generated integration code, the ISLE
instruction definitions and their accompanying Rust macro, to the
`cranelift-codegen-meta` crate.

This has the added advantage that `cranelift-assembler-x64` now can
focus exclusively on being an assembler and not being concerned with the
ISLE integration, which is substantial.

* Move lint `allow` to problem site

Apparently allowing unused variables for unimplemented parts of fixed
register instructions will not work at the macro scope; this moves the
`allow` to the offending line.

* Remove `rustfmt` of generated assembler code

Release Wasmtime 30.0.2 (#10294)

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Co-authored-by: Wasmtime Publish <wasmtime-publish@users.noreply.github.com>

Release Wasmtime 30.0.1 (#10272)

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Release Wasmtime 30.0.0 (#10250)

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Release Wasmtime 29.0.1 (#10070)

* Release Wasmtime 29.0.1

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* Add release notes

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Co-authored-by: Wasmtime Publish <wasmtime-publish@users.noreply.github.com>
Co-authored-by: Alex Crichton <alex@alexcrichton.com>

Release Wasmtime 29.0.0 (#10049)

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Release Wasmtime 28.0.1 (#10015)

* Release Wasmtime 28.0.1

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* Write release notes

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Co-authored-by: Wasmtime Publish <wasmtime-publish@users.noreply.github.com>
Co-authored-by: Alex Crichton <alex@alexcrichton.com>

Release Wasmtime 28.0.0 (#9876)

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Co-authored-by: Wasmtime Publish <wasmtime-publish@users.noreply.github.com>

Release Wasmtime 27.0.0 (#9624)

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Release Wasmtime 26.0.1 (#9561)

* Release Wasmtime 26.0.1

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* Add release notes.

---------

Co-authored-by: Wasmtime Publish <wasmtime-publish@users.noreply.github.com>
Co-authored-by: Dan Gohman <dev@sunfishcode.online>