[Fixes #81448830] remove call to setText when text sprite is created because this is before the constraint has been applied, and doing so set the text to the literal constraint string ('${this.parent.text}') rather than the computed value. It is set in the set_text setter method when the attribute is set later in the init process, so setting it early was extraneous. Added tests for the text component in text.html, moved all other smoke tests related to text into this file to keep them organized. I'd like to remove the error...html tests that are duplicated as well, but waiting to discuss with team b4 going forward. Also added labelbutton.html smoke test, as this component exhibited the symptom addressed in this bug fix.
[#81448830] Now the text attribute evaluates to the empty string if it is set by a constraint that resolves to null or undefined, or if the text attr is not set at all. Also now the text attribute is set to the value of text set between the start and end text tag, whereas before the text showed up in the sprite but the attr evaluated to undefined
Merge pull request #38 from teem2/text_constraint_regression_81448830

[Fixes #81448830] remove call to setText when text sprite is created bec...