[ACTS] Update sub-process utilities

- Redirect stderr
- Enable user to specify specific signal used for process
  termination (default is previous behavior)
- Add "wait for subprocess" routine

Change-Id: I8dea012977bbb0efa726630ac1a4db01e2800a27
1 file changed
tree: 6a962cbda10c1521a9c9304b0af0064e66d0dd28
  1. acts/