[app-mgmt-test] Do not abspath loadable apps in build

The build directory is not always absolute, so in some cases (for
example where "make" is invoked directly) the SRCDEPS will contain an
absolute path but fail to find the build rule which is a relative path.

Bug: 190442986
Change-Id: I5063de98d5b37d5be9e269d1874883a8b1c16b9a
1 file changed