Wrong rolling of output GenBank file names

Affected XML regression tests:

• 1355/test_0001.xml
• 1503/test_0001.xml

Scenario:

1. In the Workfow Designer add "Read Sequence" and "Write Sequence" elements and connect them.
2. Input two *.gb files to "Read Sequence".
3. In "Write Sequence" element set "Document format" to "GenBank".
4. In "Write Sequence" set "Accumulate objects" to "False".
5. Set "Output file" to "test_1355.gb".
6. Validate and run the workflow.
   Expected state: there are 2 output files with name "test_1355.gb" and "test_1355_1.gb" in the output folder.
   Actual state: name of the second output file is "test_1.gb" unexpectedly.