Golang cmd/internal/testdir:2_10: Test/fixedbugs/bug440_64.go failures

#!watchflakes
default <- pkg == "cmd/internal/testdir:2_10" && test == "Test/fixedbugs/bug440_64.go"

Issue created automatically to collect these failures.

Example (log):

=== RUN   Test/fixedbugs/bug440_64.go
=== PAUSE Test/fixedbugs/bug440_64.go
=== CONT  Test/fixedbugs/bug440_64.go
    testdir_test.go:147: exit status 2
        panic: runtime error: index out of range [747477] with length 2972

        goroutine 1 gp=0xc000002380 m=2 mp=0xc00004a808 [running]:
        panic({0x48e4520?, 0xc00001aea0?})
            runtime/panic.go:802 +0x168 fp=0xc0000e9388 sp=0xc0000e92d8 pc=0x45a8e48
        runtime.goPanicIndex(0xb67d5, 0xb9c)
...
        runtime.gcBgMarkWorker(0xc000376000)
            runtime/mgc.go:1463 +0xeb fp=0xc000097fc8 sp=0xc000097f38 pc=0x4555d8b
        runtime.gcBgMarkStartWorkers.gowrap1()
            runtime/mgc.go:1373 +0x25 fp=0xc000097fe0 sp=0xc000097fc8 pc=0x4555c65
        runtime.goexit({})
            runtime/asm_amd64.s:1693 +0x1 fp=0xc000097fe8 sp=0xc000097fe0 pc=0x45b0f41
        created by runtime.gcBgMarkStartWorkers in goroutine 1
            runtime/mgc.go:1373 +0x105

--- FAIL: Test/fixedbugs/bug440_64.go (1.69s)

— watchflakes

Comment From: gopherbot

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "cmd/internal/testdir:2_10" && test == "Test/fixedbugs/bug440_64.go"

2025-07-15 15:20 gotip-darwin-amd64_13 go@d826bf4d cmd/internal/testdir:2_10.Test/fixedbugs/bug440_64.go (log)

=== RUN Test/fixedbugs/bug440_64.go === PAUSE Test/fixedbugs/bug440_64.go === CONT Test/fixedbugs/bug440_64.go testdir_test.go:147: exit status 2 panic: runtime error: index out of range [747477] with length 2972 goroutine 1 gp=0xc000002380 m=2 mp=0xc00004a808 [running]: panic({0x48e4520?, 0xc00001aea0?}) runtime/panic.go:802 +0x168 fp=0xc0000e9388 sp=0xc0000e92d8 pc=0x45a8e48 runtime.goPanicIndex(0xb67d5, 0xb9c) ... runtime.gcBgMarkWorker(0xc000376000) runtime/mgc.go:1463 +0xeb fp=0xc000097fc8 sp=0xc000097f38 pc=0x4555d8b runtime.gcBgMarkStartWorkers.gowrap1() runtime/mgc.go:1373 +0x25 fp=0xc000097fe0 sp=0xc000097fc8 pc=0x4555c65 runtime.goexit({}) runtime/asm_amd64.s:1693 +0x1 fp=0xc000097fe8 sp=0xc000097fe0 pc=0x45b0f41 created by runtime.gcBgMarkStartWorkers in goroutine 1 runtime/mgc.go:1373 +0x105 --- FAIL: Test/fixedbugs/bug440_64.go (1.69s)

— watchflakes