[widgets] test-suite: start file encoding

Test cases e5, e6, z1 and z2 test the ability of a UA to use a widget- 
specified charset (ISO 8859-1); however the P&C specification states  
that a UA only has to implement UTF-8, and support for additional  
encodings is optional.

Do these test cases then really only require that a UA processes the  
package and obtains the value "ISO 8869-1" or "Windows-1252" for the  
encoding attribute, even if the start file is actually encoded in  
UTF-8 when it is served by the UA?

S