Fixed Process and ProcessBuilder to work on my system with CgiHttpKernel...

... (2.0 Backport)

- A working directory that does not exist does not work.
- Descriptors formatting.
- stream_set_blocking() takes integer not boolean as second parameter.
- Streams on Windows that didn't set to non-blocking should only fread()
  when there are bytes to read and only fclosed() while being eof. Fixes
  PHP Bug #51800. See Issue #3.