pw_build: Shell escape printed commands
pw_build: Shell escape printed commands

This makes it possible to copy and paste python_runner.py commands.

Change-Id: I4432a6bdf154920d2ef5ae50fd4b198e8921344a

google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed