dlv_test: fix TestChildProcessExitWhenNoDebugInfo to test stripped binary

[polinasok]

Following up on discussion here: #2018 (comment)
The test was bailing out early before actually trying to debug a stripped binary at this check:

delve/cmd/dlv/cmds/commands.go

Lines 891 to 902 in 2b97231

	if !headless && !allowNonTerminalInteractive {
	for _, f := range []struct {
	name string
	file *os.File
	}{{"Stdin", os.Stdin}, {"Stdout", os.Stdout}, {"Stderr", os.Stderr}} {
	if f.file == nil {
	continue
	}
	if !isatty.IsTerminal(f.file.Fd()) {
	fmt.Fprintf(os.Stderr, "%s is not a terminal, use '-r' to specify redirects for the target process or --allow-non-terminal-interactive=true if you really want to specify a redirect for Delve\n", f.name)
	return 1
	}

Modified the flags and added logging and more checks to make sure the session exits for the right reasons.

$ go test -run ^TestChildProcessExitWhenNoDebugInfo$ -v
=== RUN   TestChildProcessExitWhenNoDebugInfo
    dlv_test.go:272: time="2022-03-29T06:17:06Z" level=warning msg="CGO_CFLAGS already set, Cgo code could be optimized." layer=dlv
        2022-03-29T06:17:06Z info layer=debugger launching process with args: [/tmp/http_server.b8c49b54]
        could not launch process: could not open debug info
...

[polinasok]

Is this part designed to test that a process won't leak after the debug command exits?
Technically, when process leaks, the debugger leaks with it and the test will times out.

[aarzilli]

I don't remember, I think it didn't hang when the process leaks on linux.

[aarzilli]

I don't remember, I think it didn't hang when the process leaks on linux.

[derekparker]

LGTM

[derekparker]

Re-running CI real quick.