chimera.should-get: We expect just one sequence to be ambiguous

This test passed because the 2 matched the 241 of the read length. But this is
not what we wanted to test. We expect just one sequence to be ambiguous.

algo/tests/should-get-tests/chimera.should-get

@@ -4,5 +4,5 @@ $ Do not segment on IGL by chance
 1:IGL .* -> .* 0
 
 $ Report the sequence as AMBIGUOUS
-1:UNSEG ambiguous .* 2
+1:UNSEG ambiguous -> 1