kunit: added Python libraries for handing KUnit config and kernel

kunit_config.py:
  - parses .config and Kconfig files

kunit_kernel.py: provides helper functions to:
  - configure the kernel using kunitconfig
  - builds the kernel with the correct architecture
  - provides function to invoke the kernel and stream the output back

The kernel invocation is wrapped in a subprocess call within the module
because regular invocation of the kernel (./linux) may modify TTY
settings.

Change-Id: I488d118948b3e55c351fbfbc27dcdde9364c109a
Signed-off-by: Felix Guo <felixguoxiuping@gmail.com>
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
3 files changed