It happens that the android emulator supposedly "finishes" booting and
getprop shows bootanim=stopped and boot_completed=1. But sometimes not
all packages have been installed (`pm list packages` shows only 16
packages installed).
After around half a minute the boot animation starts spinning
(bootanim=running) again despite boot_completed=1 all the time. After
some minutes the boot animation stops again and the list of packages
contains 80 packages, among which is also the "development" package.
Only then is the device ready for `adb install` of custom packages.
This should be the last time we see the message:
Error: Could not access the Package Manager. Is the system running?
Just for completeness, we also properly disown the emulator process and
its file descriptors, since the parent shell dies but the process stays.
Pick-to: 6.3 6.2
Fixes: QTQAINFRA-4681
Change-Id: I2b9d4bdc3dac0f10d09d4f09c83b4028ebc31f48
Reviewed-by: Daniel Smith <Daniel.Smith@qt.io>