[Go] Align stack-check elision and entry PCDATA with native Go

[zhouguangyuan0718]

This follows up the runtime stack-growth support merged through #73.

The PR intentionally keeps the work in two reviewable commits:

1. Elide morestack for final-frame small leaf functions on AArch64 and X86, while keeping the entry ArgsPointerMaps STACKMAP independent. X86 also matches native Go's leaf-like handling of the zero-argument panic helpers, including the extra 8-byte CALL return-PC limit. The LLVM frontend consumes generic SSA, so it does not emit Go DUFFCOPY/DUFFZERO calls; inline memory intrinsics remain call-free instead.
2. Restore native Go's PCDATA_StackMapIndex entry sentinel of -1. ArgsPointerMaps/LocalsPointerMaps pair 0 is still serialized; runtime getStackMap normalizes -1 to bitmap 0. CFG ranges that return to entry SP depth also return to -1.

This removes the artificial 32-byte AArch64 stack-growth prefix from zero-frame leaf functions without removing their entry argument maps.

The GoALLC LLVM CI test list now includes the leaf-policy, entry-sentinel, and entry-CFG fixtures so the payload jobs exercise these contracts directly.

Validation:

• Focused leaf/stack-check and sentinel suite: 8/8 passed.
• Broader Generic/X86/AArch64 GoObj and Go CodeGen suite: 52/52 passed; go-memset-inline was excluded because its stale REP expectation already fails on the X86: Repair Go ABI state at ABI0 boundaries #76 baseline llc.
• git clang-format --diff reports no changes.

[github-actions]

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