fix nil/bounds/make panic semantics

[cpunion]

Summary

• make runtime panics carry runtime.Error values and add indexed bounds panic helpers
• check make(chan) negative/overflow sizes before allocation
• preserve nil-deref ordering for field address and pointer load paths while keeping nil array pointer len/range semantics
• add stable test/go coverage for fixedbugs bug273, issue63657, issue65417, issue72844, issue72860, and issue75327

GOROOT xfail updates

Removed darwin/arm64 xfails only for locally verified passing cases:

• fixedbugs/bug273.go
• fixedbugs/issue63657.go
• fixedbugs/issue65417.go
• fixedbugs/issue72844.go (go1.25/go1.26)
• fixedbugs/issue72860.go (go1.25/go1.26)
• fixedbugs/issue75327.go (go1.26)

Left recover/defer cases and still-failing cases out of this PR: issue4066.go, issue73916*.go, issue19040.go, issue23837.go, issue37975.go. Linux xfails remain because this worktree only verified darwin/arm64.

Tests

• /opt/homebrew/Cellar/go/1.26.0/libexec/bin/go test ./ssa ./cl -run 'TestSkipUnusedArrayDeref|TestIsLargeNonPointerValue|TestCompileLargeNilDerefInterfaceGuards' -count=1\n- /opt/homebrew/Cellar/go/1.26.0/libexec/bin/go test ./test/go -run 'TestMakeSliceAndChanPanics|TestNilAddressCalculationPanicsAfterPriorSideEffects|TestNilLoadBeforeBoolShortCircuitPanics|TestGenericUnsafeSizeofIndexPanics|TestIndexBoundsPanicTextIncludesLength|TestRangeOverNilArrayPointer|TestLenOfNilArrayPointer' -count=1\n- /tmp/llgo-fixedbugs-panic test ./test/go -run 'TestMakeSliceAndChanPanics|TestNilAddressCalculationPanicsAfterPriorSideEffects|TestNilLoadBeforeBoolShortCircuitPanics|TestGenericUnsafeSizeofIndexPanics|TestIndexBoundsPanicTextIncludesLength|TestRangeOverNilArrayPointer|TestLenOfNilArrayPointer' -count=1\n- /opt/homebrew/Cellar/go/1.26.0/libexec/bin/go test ./test/go -count=1\n- small GOROOT batches with empty xfail for Go 1.24.11, Go 1.25.7, and Go 1.26.0 over fixedbugs/(bug273|issue63657|issue65417|issue72844|issue72860|issue75327).go\n- Go 1.26.0 same small GOROOT batch with the default xfail file after deletion\n