[dsf-gdb] tests: Check if a line tag is defined more than once

As a safety net, fail if a line tag is defined more than once.

Also, allow calling resolveLineTagLocations more than once for a single
test.

Change-Id: I0832d3d28c4d688c38fd33dfc668b0ec6b8c4ffa
Signed-off-by: Simon Marchi <simon.marchi@polymtl.ca>
1 file changed