Autotests: loading SMARTS files

[urszula-gawlowska]

It is planned to automate tests for loading SMARTS files, for example:

• few atom properties set up:
  benzene_x6_H5_D4.zip
• the one from failing Indigo tests:
  isomorphic_read_errors.zip

To remember - add also test cases based on done tickets:

• Custom query is not correctly represented on canvas - only atom number is displayed, preview is not displayed #3502 Custom query is not correctly represented on canvas - only atom number is displayed, preview is not displayed
• valid SMARTS with cycles cause error in loader Indigo#1292 valid SMARTS with cycles cause error in loader (use this as example of SMARTS for loading SMARTS tests)
• New S-Group type Query component level grouping Indigo#1287 New S-Group type Query component level grouping (remember about testing S-Group with loading tests)