Edge and IE occasionally fail snapshot test(s)

[vweevers]

Edge failed a test in a Travis/Sauce Labs job. See #157 (comment).

[vweevers]

I can replicate it locally, also in IE, repeating the snapshot tests 1000 times. Side note: they sometimes just stall after opening a few hundred db's, but that's another issue.

I cannot replicate it in Chrome or FF. This suggests there is a bug in IE/Edge's IndexedDB implementation. I tried to find a relevant test in the W3C IndexedDB test suite (which lists many failures for Edge) but came up short.

[vweevers]

Side note: they sometimes just stall after opening a few hundred db's, but that's another issue.

Correction: they (or at least IE) error on this line - because that test asserts that an iterator can read a key that was deleted after the iterator/snapshot/transaction was created - and IE apparently fails that test (too).

I'm inclined to tag this as wontfix and move on.

Overall, IE failed 4 of 1690 tests. Edge failed 5 of 3000 tests. Chrome, FF and Opera never fail (I ran 6000+ tests on each).

[vweevers]

@ralphtheninja FYI ^^. If you see a snapshot test failing in future builds, restart them. If and when it becomes a nuisance we can consider skipping these tests in IE/Edge.

[vweevers]

Closing due to #86