forminput: Enable Comma-seperated List in #forminput parser function
The "form=" parameter for #forminput can now take a comma-separated
list of form names as a value to be displayed in the dropdown.
Form names with a comma must be escaped using a backslash: "\,".
Improved upon: I615bdf1da6b01ff3587f43f4282422fa71c3abaa
Bug: T187110
Change-Id: I8f29046b22c94ac661a9f8a9e4366a2394a87378