Sync to upstream/release/598

[andyfriesen]

• Include windows.h rather than Windows.h to make things compile on MinGW.
• Custom implementation of timegm/os.time for all platforms
• Disable builtin constant folding when getfenv/setfenv are used
• Fixes Inline can break repeat until loops with contiune statement #1042
• Fixes Continue in repeat until loop can close upvalues before the until condition is executed #1043

New Type Checker

• Initial work toward type states.
• Rework most overloadable operators to use type families.
• Initial work toward our new nonstrict mode.

Native Codegen

• Fix native code generation for dead loops
• Annotate top-level functions as cold
• Slightly smaller/faster x64 Luau calls
  • emitInstCall used to not set savedpc itself, but now it does for consistency with all other implementations
• Implement cmov support for X64
• Fix assertion in luau-compile when module is empty
• Optimize A64 calls at some code size cost
• Inline constant array index offset into the load/store instruction
• Increase x64 spill slots from 5 to 13