[BUGFIX beta] Do not compare meta in deepEqual.

In non-ES5 browsers the `QUnit.deepEqual` will also compare
`__ember_meta__` property (which is highly unlikely to match).

This adds a helper method named `withoutMeta` for these tests
specifically.
Merge pull request #5159 from rjackson/fix-test-failures-in-non-es5

[BUGFIX beta] Do not compare meta in deepEqual.