XMLBearTest: Add get_testfile_path
XMLBearTest: Add get_testfile_path

... to create absolute test-file paths used during tests. This commit
merges the duplicated test-file-path-functionality.

coala-analyzer/coala-bears,refeed/coala-bears,aptrishu/coala-bears,ankit01ojha/coala-bears,aptrishu/coala-bears,ankit01ojha/coala-bears,refeed/coala-bears,refeed/coala-bears,coala-analyzer/coala-bears,coala/coala-bears,coala/coala-bears,coala-analyzer/coala-bears,ankit01ojha/coala-bears,refeed/coala-bears,coala-analyzer/coala-bears,coala-analyzer/coala-bears,ankit01ojha/coala-bears,refeed/coala-bears,refeed/coala-bears,coala/coala-bears,coala-analyzer/coala-bears,coala-analyzer/coala-bears,refeed/coala-bears,ankit01ojha/coala-bears,refeed/coala-bears,coala/coala-bears,aptrishu/coala-bears,refeed/coala-bears,refeed/coala-bears,coala/coala-bears,aptrishu/coala-bears,ankit01ojha/coala-bears,coala/coala-bears,ankit01ojha/coala-bears,aptrishu/coala-bears,ankit01ojha/coala-bears,coala/coala-bears,aptrishu/coala-bears,aptrishu/coala-bears,aptrishu/coala-bears,coala/coala-bears,aptrishu/coala-bears,ankit01ojha/coala-bears,ankit01ojha/coala-bears,coala/coala-bears,coala-analyzer/coala-bears,coala/coala-bears,coala/coala-bears,coala/coala-bears,aptrishu/coala-bears,coala-analyzer/coala-bears,aptrishu/coala-bears,ankit01ojha/coala-bears,refeed/coala-bears