EqualObject Matcher ignores additional fields

[killianmuldoon]

Expected internal/matchers.EqualObject to return false when the compared object has more fields than the original object. Currently if the original object has more fields than the actual the objects are returned as equal.

This is unexpected behaviour for those using the EqualObject matcher in tests.

Unit tests will be added to the matcher to ensure it's functioning as expected.

/kind bug
/area testing

/cc @sbueringer

[vincepri]

/milestone v1.1