code: public boolean containsInstruction(InstructionHandle handle) {
          Iterator<InstructionHandle> i = instructionIterator();
          while (i.hasNext()) {
              if (i.next() == handle) {
                  return true;
              }
          }
          return false;
      }
docs: Return whether or not the basic block contains the given instruction.
  
  @param handle
  the instruction
  @return true if the block contains the instruction, false otherwise