This signifigantly improves the startup time of soong-built
python binaries. For example, running
`m apexer && time out/host/linux-x86/bin/apexer` gives
0.734s before this cl, and 0.094s after.
Fixes: 259718110
Test: Presubmits
Change-Id: Ib19e83e2c60c39a849525be117279c318de3afa7
This test adds a number of checks for the visible python state inside a
hermetic par file.
Test: build/soong/python/tests/runtests.sh
Change-Id: I7188d862a309a09623169e1f967bde86707d41af