embedded_launcher causes the python interpreter to be bundled in the
built zip file. This is beneficial because:
- You can export the built executable and run it on systems
without python or an old version of python. The CI servers have python
3.7, so it's useful to update that.
- Because the python version is known, the python sources will be
precompiled.
- It will start running the code directly from the zip file, without
extracting the binary to a temporary directory like non-embedded
launcher binaries. This is particuarly useful because some developers
use the extracted files directly instead of using
`importlib.resources`, so having the non-extracting implementation
gives them a nudge in the right direction.
Make embedded_launcher the default so that more developers will do the
right thing when developing python programs.
Bug: 331488610
Test: Presubmits
Change-Id: Ideb113a1d4d3b29ac04d57a48d111a99f77b2dfc
8a038ed871