Bug 650161 - Fix bug in arena selection logic r=terence

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extra : rebase_source : 2a9e5f4eb0bd6dade2c98125d43911ae2751d79f
Bug 650161 - Report GC invocation kind in stats r=terrence

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extra : rebase_source : 914b990289c6a9ea94219b2db606a96ac3b9ec76
Bug 650161 - Update the list of test timeouts to ignore in CGC zeal tests r=terrence

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extra : rebase_source : a095f53a0b4a6ba0c26e94ba595b9bd3c2be5961