Make no-relocate the default.

With the move to not support relocatable oat files, testing "relocate"
does not make sense anymore (the runtime would just discard the prebuild
oat file and generate a new one in dalvik-cache).

Just make no-relocate the default for now. We can remove relocation types
once Richard is done removing relocation.

Test: test-art-host test-art-target
bug:33192586

Change-Id: If39a0ad63451c68d4cfbbb26b767ad98b97d208e