restricted_trace_perf: Change loop order

Before this CL we are doing:

  For each renderer
    For each loopcount
      For each trace
         Do the test
  Write out summary of all results

We don't get useful data unless the entire script completes.

We are seeing some devices disconnect more often, so let's
change the order to preserve data.

The loop becomes:

  For each trace
    For each iteration
      For each renderer
        Do the test
    Write out summary for the trace

Output becomes:

  native_1945_air_force
  vulkan_1945_air_force

  native_1945_air_force
  vulkan_1945_air_force

  etc.

The final output is unchanged. Raw data will be in a different order.

Bug: b/369203495
Change-Id: I09b189b5c578dd520123e4ac850018e75b219aa8
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5884633
Commit-Queue: Cody Northrop <[email protected]>
Reviewed-by: Roman Lavrov <[email protected]>