Sync to upstream/release/623

[alexmccord]

What's changed?

New Type Solver

• Unification of two fresh types no longer binds them together.
• Replaced uses of raw emplace with emplaceType to catch cyclic bound types when they are created.
• SetIndexerConstraint is blocked until the indexer result type is not blocked.
• Fix a case where a blocked type got past the constraint solver.
• Searching for free types should no longer traverse into ClassTypes.
• Fix a corner case that could result in the non-testable type ~{}.
• Fix incorrect flagging when any was a parameter of some checked function in nonstrict type checker.
• IterableConstraint now consider tables without __iter to be iterables.

Native Code Generation

• Improve register type info lookup by program counter.
• Generate type information for locals and upvalues

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Internal Contributors

Co-authored-by: Aaron Weiss aaronweiss@roblox.com Co-authored-by: Alexander McCord amccord@roblox.com Co-authored-by: Andy Friesen afriesen@roblox.com Co-authored-by: James McNellis jmcnellis@roblox.com Co-authored-by: Vighnesh Vijay vvijay@roblox.com Co-authored-by: Vyacheslav Egorov vegorov@roblox.com