Upgrade zone.js to 0.8 series.
Upgrade zone.js to 0.8 series.

0.7 is buggy and patches ``Error`` in a way that makes test fails.

mangalam-research/wed,mangalam-research/wed,mangalam-research/wed,lddubeau/wed,lddubeau/wed,mangalam-research/wed,lddubeau/wed,lddubeau/wed