Fixing witness generation for Radians

[sohah]

Merge reques #24 added implementation for toRadians and toDegrees, however, we generate the wrong witness in the witness.graphml even though the correct model is populated on the PathCondition. Looks we just need to propagate this value to the witness.

To replicate:

1. clone the sv-comp branch on Java-Ranger repo
2. use the randian example from sv-comp (here)
3. use the configuration in the config.java

Below is the graphml generated

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<graphml xmlns="http://graphml.graphdrawing.org/xmlns" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <key attr.name="originFileName" attr.type="string" for="edge" id="originfile">
    <default>&lt;command-line&gt;</default>
  </key>
  <key attr.name="isViolationNode" attr.type="boolean" for="node" id="violation">
    <default>false</default>
  </key>
  <key attr.name="isEntryNode" attr.type="boolean" for="node" id="entry">
    <default>false</default>
  </key>
  <key attr.name="producer" attr.type="string" for="graph" id="producer"/>
  <key attr.name="startline" attr.type="int" for="edge" id="startline"/>
  <key attr.name="assumption" attr.type="string" for="edge" id="assumption"/>
  <key attr.name="assumption.scope" attr.type="string" for="edge" id="assumption.scope"/>
  <key attr.name="witness-type" attr.type="string" for="graph" id="witness-type"/>
  <graph edgedefault="directed">
      <data key="witness-type">violation_witness</data>
      <data key="producer">SPF</data>

       <node id="n0">
           <data key="entry">true</data> <data key="violation">true</data>
       </node>
  </graph>
</graphml>

[SalmaneKhalili]

@sohah Ill start looking into this as well