Make run-tests.py work with the BigBenchmarks
Use flag variable
Show output dir at the start of run-tests.py
Merge pull request #81 from alancutter/printOutDir

Print output dir at start of run-tests.py
Merge pull request #80 from alancutter/runBigTests

Make run-tests.py work for the BigBenchmarks
Parameterize big benchmarks by animated property

We create 5 versions for each CSS animation and transition benchmark:-
- compositor-transform = transform animation on compositor thread
- mainthread-transform = transform animation on main thread
- opacity = opacity animation on compositor thread
- px-height = height animation on main thread
- specific-color = color animation on main thread

For web animations, we create the above 5 versions and 3 more:-
- em-height = height animation responsive to font size
- inherit-height = height animation responsive to parent height
- current-color = color animation responsive to parent color

run-big-benchmarks.py is updated to use the generated versions.

A small number of benchmarks fail, sometimes because we have too many
elements. For example, in one run the following failed:-
- web-animations-staggered-chaining-compositor-transform.html
- css-animations-staggered-chaining-by-inserting-style-element-px-height.html
- css-transitions-simultaneous-by-inserting-style-element-specific-color.html
- css-transitions-staggered-chaining-by-updating-class-px-height.html
- css-animations-staggered-chaining-by-inserting-style-element-specific-color.html
- css-animations-staggered-chaining-by-inserting-style-element-mainthread-transform.html
- css-transitions-simultaneous-by-inserting-style-element-px-height.html