(#6167) - fix and improve test scripts

[nolanlawson]

I was trying to do some simple performance tests:

PERF=1 CLIENT=selenium:chrome GREP=temp-views ITERATIONS=5 npm t

And I found that basic stuff was not working. So I fixed several issues with our test scripts, notably:

• results.completed being called too early (end of test suite, not end of all test suites)
• not able to test memory in Node
• GREP not working correctly with marking results.completed
• not able to specify number of iterations
• object printed to console too large, too hard to read

Our test scripts could probably use a heck of a lot more refactoring, but for the time being they're at least usable now.