tests/edje: add comprehensive edje reloading test
Summary:
this verifies:
- successfully loading a file
- emission of "load" signal when performing a file load
- swallowing an object
- no-op of file load operation on same file if mtime is unchanged
- successfully reloading the same file if the mtime has changed
- preserving user-defined data across file reloads
Depends on D9877
Reviewers: cedric
Reviewed By: cedric
Subscribers: reviewers, committers
Tags: efl
Differential Revision: https://phab.enlightenment.org/D9878