Sync to upstream/release/562

[vegorov-rbx]

• Fixed rare use-after-free in analysis during table unification

A lot of work these past months went into two new Luau components:

• A near full rewrite of the typechecker using a new deferred constraint resolution system
• Native code generation for AoT/JiT compilation of VM bytecode into x64 (avx)/arm64 instructions

Both of these components are far from finished and we don't provide documentation on building and using them at this point.
However, curious community members expressed interest in learning about changes that go into these components each week, so we are now listing them here in the 'sync' pull request descriptions.

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New typechecker can be enabled by setting DebugLuauDeferredConstraintResolution flag to 'true'.
It is considered unstable right now, so try it at your own risk.
Even though it already provides better type inference than the current one in some cases, our main goal right now is to reach feature parity with current typechecker.
Features which improve over the capabilities of the current typechecker are marked as '(NEW)'.

Changes to new typechecker:

• Regular for loop index and parameters are now typechecked
• Invalid type annotations on local variables are ignored to improve autocomplete
• Fixed missing autocomplete type suggestions for function arguments
• Type reduction is now performed to produce simpler types to be presented to the user (error messages, custom LSPs)
  • Internally, complex types like '((number | string) & ~(false?)) | string' can be produced, which is just 'string | number' when simplified
• Fixed spots where support for unknown and never types was missing
• (NEW) Length operator '#' is now valid to use on top table type, this type comes up when doing typeof(x) == "table" guards and isn't available in current typechecker

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Changes to native code generation:

• Additional math library fast calls are now lowered to x64: math.ldexp, math.round, math.frexp, math.modf, math.sign and math.clamp