runtime: preserve interface compare panic errors

[cpunion]

Summary

• Preserve runtime.Error/error panic values for runtime-generated panics used during interface comparison evaluation.
• Route failed non-comma-ok type assertions through a runtime helper so recovered values are error-like, matching Go's runtime behavior.
• Add nil-deref guarding for interface dereferences consumed directly by comparisons, covering fixedbugs/issue32187.go.
• Add stable test/go coverage for interface comparison evaluation panics and remove fixed issue32187.go xfails.

Tests

• go test ./test/go -run 'TestInterfaceCompare|TestNilPointer' -count=1
• go run -tags=dev ./cmd/llgo test -run '^TestInterfaceCompare' ./test/go
• go test ./ssa -run 'TestTypeAssert|TestMakeInterface|TestBinOp' -count=1
• (cd runtime && go test ./internal/runtime ./abi -count=1)
• LLGO_BUILD_CACHE=off go test ./cl -run 'TestRunAndTestFromTestgo/(cursor|ifaceprom)$' -count=1
• LLGO_BUILD_CACHE=off go test ./cl -run 'TestCompileLargeNilDerefInterfaceGuards|TestRunAndTestFromTestgo' -count=1
• go test ./test/goroot -run TestGoRootRunCases/fixedbugs/issue32187.go -count=1 -args -goroot "$(go env GOROOT)" -dirs fixedbugs -case '^fixedbugs/issue32187\.go$' -xfail /dev/null -run-timeout=30s -build-timeout=3m
• go test ./test/goroot -run TestGoRootRunCases/fixedbugs/issue32187.go -count=1 -args -goroot "$(go env GOROOT)" -dirs fixedbugs -case '^fixedbugs/issue32187\.go$' -run-timeout=30s -build-timeout=3m

Notes

• Targeted GOROOT run used the current machine GOROOT (go env GOROOT, Go 1.24.11). Full GOROOT CI remains slow/disabled here; relying on normal PR CI from the fork branch.
• No manual workflow_dispatch was started. If the manual GOROOT workflow cannot resolve fork refs, document that in this PR rather than pushing to xgo-dev/llgo.

[cpunion]

修复进展更新：

根因：失败 job test (ubuntu-latest, 19) 的完整日志显示 cl/ssa 的 FileCheck golden 仍在匹配旧的 type assertion 失败 IR：先构造 string eface 再调用 runtime.Panic。本 PR 已把 type assertion 失败路径改为 runtime.PanicTypeAssertionError 以保留 runtime error 语义，因此旧 golden 在 vargs、any、funcdecl、makemap、tpabi、typed 以及当前 xgo-dev/main 新增的 genericembediface 上失配。分支也落后于 xgo-dev/main，所以本地起初没有 CI merge 中的 genericembediface 用例。

修复：

• 合入当前 xgo-dev/main，让 PR 分支和 CI merge 面一致。
• 刷新相关 cl/_test* FileCheck，断言新的 runtime.PanicTypeAssertionError 调用。
• 在 test/go/interface_uncomparable_panic_test.go 增加 T comparable 且 T=any 的动态不可比较值覆盖，确保功能覆盖落在 test/go。

本地测试：

• go test ./test/go -run 'TestInterfaceCompare|TestComparableTypeParamInterfaceValuePanics' -count=1 -v ✅
• go test ./cl -run 'TestRunAndTestFromTestgo/genericembediface|TestRunAndTestFromTestrt/(any|funcdecl|makemap|tpabi|typed)|TestRunAndTestFromTestdata/vargs' -count=1 -v ✅
• go test ./ssa -run 'TestFromTestgo/genericembediface|TestFromTestrt/(any|funcdecl|makemap|tpabi|typed)|TestFromTestdata/vargs' -count=1 -v ✅
• go test ./test/go ✅
• git diff --check ✅

新 head：957cc66468e4454bb19ad941d93683d0747f2168。CI 已重新触发并正在排队/运行中；PR 保持 draft。

[cpunion]

2026-05-24 verification update for fixedbugs/issue32187.go:

• Classified as in-scope for this PR: interface-to-concrete comparison evaluation and panic ordering. The case checks that comparison lowering does not short-circuit away RHS/LHS panics from type assertions, bounds checks, and nil dereferences.
• Coverage is already present in test/go/interface_uncomparable_panic_test.go via TestInterfaceCompareEvaluationPanicsAreRuntimeErrors, mirroring the upstream issue32187.go subcases. The nil-deref entries are covered only as comparison evaluation-order subcases; this PR does not expand into broader nil-specific work, chan, print, recover, GC, liveness, finalizer, or goroutine areas.
• fixedbugs/issue32187.go xfails for darwin/arm64 and linux/amd64 have been removed in this branch. No remaining issue32187.go xfail is present.

Local verification on /Users/lijie/sdk/go1.26.0 and this branch HEAD 957cc66468e4454bb19ad941d93683d0747f2168:

• go test ./test/goroot -run TestGoRoot -count=1 -args -goroot /Users/lijie/sdk/go1.26.0 -dirs fixedbugs -case "^fixedbugs/issue32187\\.go$" -directive-mode legacy -> pass
• go test ./test/go -run TestInterfaceCompareEvaluationPanicsAreRuntimeErrors -count=1 -> pass
• go test ./test/go -count=1 -> pass
• go test ./ssa ./cl -count=1 -> pass (cl took ~546s)
• (cd runtime && go test ./... -run TestNonExistent -count=1) -> pass/no test failures

Note: go test ./runtime/... -count=1 from the repo root fails at package discovery because runtime/ is a nested module; the runtime module test above is the applicable form.

[cpunion]

Additional runtime module check for the same 2026-05-24 verification:

• (cd runtime && go test ./internal/runtime ./abi -count=1) -> pass (runtime/internal/runtime has no test files, runtime/abi passed).