runCount in runner.js should be renamed to iterationCount

runCount in runner.js should be renamed to iterationCount
https://bugs.webkit.org/show_bug.cgi?id=102208

Reviewed by Tony Chang.

Prior to this patch, there were terminology confusions between "runs" and "iterations".
The term "run" should refer to running a performance test once, and "iteration" should
refer to one measurement in the test. i.e. Executing run-perf-should once will result in
a single "run" of performance tests and each test may execute multiple "iterations"
to complete the run.

Unfortunately, we still overload the meaning of "runs" in "runs/s" (is "function calls/s")
but that could be addressed in a separate patch.

* Animation/balls.html:
* DOM/DOMTable.html:
* DOM/resources/dom-perf.js:
* Layout/floats_100_100.html:
* Layout/floats_100_100_nested.html:
* Layout/floats_20_100.html:
* Layout/floats_20_100_nested.html:
* Layout/floats_2_100.html:
* Layout/floats_2_100_nested.html:
* Layout/floats_50_100.html:
* Layout/floats_50_100_nested.html:
* Layout/subtree-detaching.html:
* Parser/html5-full-render.html:
* SVG/SvgHitTesting.html:
* resources/runner.js:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@134637 268f45cc-cd09-0410-ab3c-d52691b4dbfc