curTestSuiteNum fixes

Currently `curTestSuiteNum` is updated for every file that is run, restricting each file to one test suite per file.  
This was causing issues in files with multiple sets of tests:
- stepTimeout uses an id of `<filenum>_<stepnum>`, and `stepTimeout` stops polling if the id matches
- if a subsequent `testSuite` runs in the same file, it will have the same `testSuiteId`, causing potential misfires of `stepTimeout`

This separates file count from test suite count, eliminating the `stepTimeout` problem, and allowing multiple `testSuite`s per file.