launcher.
For Python2, we bundle embedded launcher as bootstrapper within every
.par file. This feature is only enabled for linux_x86_64 for now. We
provide a user flag: hermetic_enabled within bp file. By default, Pyhon2
still use classic bootstrapping way to construct .par file and relys on
host interpreter. Once embedded_launcher is enabled, launcher will be
used to bootstrap .par file and execute user program.
For Python3, the launcher will be ready soon, and for now it still relys
on classic bootstrapping.
Test: Real example is used to test.
Bug: b/63018041
Change-Id: I28deba413d8ad3af407595e46f77d663e79a3705