... because readline library (or libtinfo) seems to cause SEGV
internally even with Readline 8.1.
This SEGV is caught as SystemStackError, which leads to a test failure.
20211109T030008Z.fail.html.gz
```
1) Failure:
TestReadline#test_interrupt_in_other_thread [/home/chkbuild/chkbuild/tmp/build/20211109T030008Z/ruby/test/readline/test_readline.rb:568]:
Unknown failure with exit status pid 13097 exit 1
Log: ** START **Readline::VERSION is 8.1.
/home/chkbuild/chkbuild/tmp/build/20211109T030008Z/tmp/interrupt_in_other_thread20211109-6272-kcfqxo:13:in `readline': stack level too deep (SystemStackError)
from /home/chkbuild/chkbuild/tmp/build/20211109T030008Z/tmp/interrupt_in_other_thread20211109-6272-kcfqxo:13:in `block in <main>'
/home/chkbuild/chkbuild/tmp/build/20211109T030008Z/tmp/interrupt_in_other_thread20211109-6272-kcfqxo:13:in `readline': stack level too deep (SystemStackError)
from /home/chkbuild/chkbuild/tmp/build/20211109T030008Z/tmp/interrupt_in_other_thread20211109-6272-kcfqxo:13:in `block in <main>'
```
Readline seems to emit an escape sequence `"\e[?1034h` at an
unpredictable timing when `TERM=xterm` or something.
This leads to a noisy random test failure.
20211102T063005Z.fail.html.gz
```
1) Failure:
TestReadline#test_modify_text_in_pre_input_hook [/home/chkbuild/chkbuild/tmp/build/20211102T063005Z/ruby/test/readline/test_readline.rb:404]:
<"> hello world\n"> expected but was
<"\e[?1034h> hello world\n">.
```
This test is for Ruby's readline extension, not for readline library
itself. So here this change force to use "TERM=vt100" to run the tests.
- Capture that the child is started by initial log line.
- More robust handling of child status reaping.
- Direct exit without sucess mesage if `#readline` receives input.
