Fixed XFormInstanceParser test and removed old tests that used hard-coded fixtures
Fixed XFormInstanceParser test and removed old tests that used hard-coded fixtures

mainakibui/kobocat,wesley1001/formhub,piqoni/onadata,smn/onadata,SEL-Columbia/formhub,SEL-Columbia/formhub,smn/onadata,smn/onadata,spatialdev/onadata,spatialdev/onadata,awemulya/fieldsight-kobocat,awemulya/fieldsight-kobocat,qlands/onadata,GeoODK/formhub,mainakibui/kobocat,awemulya/fieldsight-kobocat,ultimateprogramer/formhub,eHealthAfrica/formhub,SEL-Columbia/formhub,qlands/onadata,hnjamba/onaclone,sounay/flaminggo-test,makinacorpus/formhub,jomolinare/kobocat,jomolinare/kobocat,kobotoolbox/kobocat,sounay/flaminggo-test,ehealthafrica-ci/onadata,ehealthafrica-ci/formhub,makinacorpus/formhub,qlands/onadata,mainakibui/kobocat,jomolinare/kobocat,ehealthafrica-ci/onadata,ehealthafrica-ci/formhub,kobotoolbox/kobocat,ehealthafrica-ci/onadata,ultimateprogramer/formhub,GeoODK/onadata,piqoni/onadata,GeoODK/onadata,makinacorpus/formhub,eHealthAfrica/formhub,piqoni/onadata,hnjamba/onaclone,GeoODK/onadata,kobotoolbox/kobocat,GeoODK/formhub,ultimateprogramer/formhub,ehealthafrica-ci/onadata,GeoODK/onadata,hnjamba/onaclone,sounay/flaminggo-test,smn/onadata,hnjamba/onaclone,mainakibui/kobocat,SEL-Columbia/formhub,spatialdev/onadata,piqoni/onadata,awemulya/fieldsight-kobocat,wesley1001/formhub,eHealthAfrica/onadata,makinacorpus/formhub,ehealthafrica-ci/formhub,ultimateprogramer/formhub,GeoODK/formhub,eHealthAfrica/formhub,qlands/onadata,sounay/flaminggo-test,eHealthAfrica/onadata,ehealthafrica-ci/formhub,kobotoolbox/kobocat,wesley1001/formhub,eHealthAfrica/onadata,jomolinare/kobocat,wesley1001/formhub,eHealthAfrica/formhub,spatialdev/onadata