xref_parser.t: Fix malformed synthetic UniProt DR lines
xref_parser.t: Fix malformed synthetic UniProt DR lines

According to the UniProt Knowledgebase, the data in a line should begin
on the 6th characters - implying that each two-letter line prefix should
be followed by three spaces. However, while generating synthetic DR
lines in the test we only inserted two. Fix this.

Ensembl/ensembl,Ensembl/ensembl,james-monkeyshines/ensembl,Ensembl/ensembl,Ensembl/ensembl,james-monkeyshines/ensembl,james-monkeyshines/ensembl,james-monkeyshines/ensembl