Case: invoke load() on an element should reject pending promises in order.
Expected result: the pending promises are rejected in order.
MozReview-Commit-ID: AJMX7uLTEN0
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extra : rebase_source : cd5e704f28db634d3700c9995097577a30a47549
extra : source : 9e41353b32c2c4674ac609b202efca8dabbbb1b5
Kaku Kuo