Checks that BreakpointManager.possibleBreakpoints returns correct locations

Locations for first line
All locations
location(2, 8)
location(2, 16)
location(2, 26)
location(2, 37)
location(2, 40)
location(2, 42)
location(2, 53)
location(2, 55)
location(3, 8)
location(3, 16)
location(4, 8)
location(4, 15)
Existing location by position
location(2, 37)
Not existing location by position