show count of test failures

Dependencies

• [2] ORRSP7FV deduce test names on failures
• [3] KKMFQDR4 editing source code from within the app
• [*] 3QNOKBFM beginnings of a test harness

Change contents

• replacement in app.lua at line 140
  [2.60589]→[2.60589:60659](∅→∅)
  − error('There were test failures:\n\n'..table.concat(Test_errors))
  [2.60589]

  [2.60659]
  + error(('There were %d test failures:\n\n%s'):format(#Test_errors, table.concat(Test_errors)))