Add a -P option to fs_config_generate that allows us to filter on
a comma separated partition whitelist or minus prefixed -blacklist.
A partition is defined as accessible as <partition>/ or
system/<partition>/.
No change for legacy, where no -P flag is specified.
For system.img, but not vendor, oem or odm file references:
fs_config_generate -P -vendor,-oem,-odm
For vendor.img file references:
fs_config_generate -P vendor
For oem.img file references:
fs_config_generate -P oem
For odm.img file references:
fs_config_generate -P odm
Add and fortify tests for each of these cases.
SideEffects: none
Test: gTest host fs_config-unit-test
Bug: 36071012
Change-Id: I0537453bb289d41ef98ad76e69f78ae49358a1b3