[INTERNAL] sap.ui.test.Opa5 trying to get my docu back

Change-Id: I5a26bc685de9663e52f6e508ac384cb013e119e1
[FIX] replace escaped empty string in mixin default parameter value

- the sapLess-parser has problems with an escaped empty string as
default value for the parametric mixin. Therefore we need to temporarily
use a parameter assigning the default value

Change-Id: I1594015e3248c284d3f24b2c9696e507d81190db
Merge "[FIX] replace escaped empty string in mixin default parameter value"
Merge "[INTERNAL] sap.ui.test.Opa5 trying to get my docu back"