[JSC] Add aligned label annotation to offlineasm

https://bugs.webkit.org/show_bug.cgi?id=270699

Reviewed by Yusuke Suzuki and Justin Michaud.

To express some programs like the InPlaceInterpreter we need to align
instructions to specific boundaries (such as 256).

We currently to do this via `emit ".balign 256, 0xcc"' (for instance)
but this is not reliable on armv7 as its globaladdr implementation can
insert code unpredictably (from the point of view of the offlineasm
user), hence breaking the alignment.

This adds an aligned label annotation which implements this
functionality in offlineasm.

* Source/JavaScriptCore/llint/InPlaceInterpreter.asm:
* Source/JavaScriptCore/llint/LowLevelInterpreter.cpp:
* Source/JavaScriptCore/offlineasm/asm.rb:
* Source/JavaScriptCore/offlineasm/ast.rb:
* Source/JavaScriptCore/offlineasm/backends.rb:
* Source/JavaScriptCore/offlineasm/parser.rb:
* Source/JavaScriptCore/offlineasm/transform.rb:

Canonical link: https://commits.webkit.org/276085@main