(PUP-2750) Fix aggregate profiler spec tests on windows

It appears that on Windows, the precision of the Time object is
not fine enough to guarantee that we'd get a non-zero value
for the empty code blocks that we were timing in our tests.

This commit simply adds a 10ms sleep to the tests to ensure that
that enough time will have passed for us to be able to make
an assertion that the elapsed time was greater than zero.