Task can be one of "executable" or "microdroid_launcher".
When it is a microdroid_launcher task, microdroid_manager find the
target library in /mnt/apk/lib/{abi}/, and then executes it via
microdroid_launcher.
Bug: 186396080
Test: MicrodroidHostTestCases
Test: /system/bin/microdroid_manager in microdroid launched with
default configuration.
it should run testapk's MicrodroidTestNativeLib.so
Change-Id: I065f5c5d789e6a96fd658a52ed8533f42b1cbc42
Jooyung Han