introduction of testprocess output capture stuck windows test machine

[judovana]

The PR of https://github.com/pmikova/java-runtime-decompiler/pull/175 introduced capturing of subprocess's stdout and err. Since then windows cli never fnished.

possible reasons:

• the reading threads are not daemon threads
• kill is waiting for stdout/err to be read
• stdout/err is nor read until process is killed
• all above

[judovana]

fixed