Do not run init CTS test on secondary ABI

Init unit tests refer to libraries that do not exist for the
secondary ABI, and we'd rather test the libraries on the device than
statically link them, so only test the primary ABI.

Init will only run on the primary ABI in any case, and doesn't have
much arch specific code in it.

Bug: 143560509
Test: build
Change-Id: I3c1883b3b55e5a06391d2885242f38c74eab621d