FELIX-3585: don't assume a binary reference starting with [VBCISDFJZ] is a primitive type

... because it could be a class in the default package such as JDOMAbout.

See https://issues.apache.org/jira/browse/FELIX-3585 for original issue and test project.

Note: this fix assumes that primitive type references will only be single letters and anything longer will be a class reference. If this is not the case (I don't know enough about who calls this code to be sure of this) then the fix will need adjusting accordingly.