Add IExplodedBasicBlock.getOriginalNumber()

This method is useful when reasoning about SSAPiStatements, as their
successor block number refers to original basic blocks, not exploded
blocks.

com.ibm.wala.core/src/com/ibm/wala/ssa/analysis/ExplodedControlFlowGraph.java

@@ -634,6 +634,11 @@ public class ExplodedControlFlowGraph implements ControlFlowGraph<SSAInstruction
       }
       return "ExplodedBlock[" + getNumber() + "](original:" + original + ")";
     }
+
+    @Override
+    public int getOriginalNumber() {
+      return original.getNumber();
+    }
   }
 
   @Override

com.ibm.wala.core/src/com/ibm/wala/ssa/analysis/IExplodedBasicBlock.java

@@ -34,4 +34,10 @@ public interface IExplodedBasicBlock extends ISSABasicBlock {
    */
   public SSAGetCaughtExceptionInstruction getCatchInstruction();
 
+  /**
+   * get the number of the original basic block containing the instruction of
+   * this exploded block
+   */
+  public int getOriginalNumber();
+
 }