When the script has trouble parsing info for a step, it's supposed to
remove that step from the list of steps to not cause further problems
with the script (and log an error). Instead, it was being removed while
iterating the same list which caused malformed tables.

Bug: angleproject:4610
Change-Id: Iff8bfd77eae227907e78660183c79221d4d305a8
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2180342Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>