[JSC] Split super complicated IC code generation clause into three di…

…fferent ones

https://bugs.webkit.org/show_bug.cgi?id=274429
rdar://128435898

Reviewed by Justin Michaud.

Load, GetGetter, CustomValueGetter, CustomValueSetter, CustomAccessorGetter, CustomAccessorSetter, Getter, Setter, and IntrinsicGetter are
sharing one switch-clause, and it makes code incredibly complicated and hard to follow. Let's just split them into three.

1. Load, GetGetter
2. CustomValueGetter, CustomValueSetter, CustomAccessorGetter, CustomAccessorSetter
3. Getter, Setter, IntrinsicGetter

This significantly reduces complexity for simple IC (like Load), and it also improves some code generation for CustomAccessorGetter / CustomAccessorSetter,
where we are unnecessarily loading property owner GPR before.

* Source/JavaScriptCore/bytecode/InlineCacheCompiler.cpp:
(JSC::InlineCacheCompiler::generateImpl):

Canonical link: https://commits.webkit.org/279047@main