code: @Nullable
      private TryBlock findBlockWithStart(int pc) {
  
          for (TryBlock block : blocks) {
              if (block.atStartPC(pc)) {
                  return block;
              }
          }
  
          return null;
      }
docs: looks for an existing try block that has this pc as a start of the try
  
  @param pc
  the current program counter
  @return the tryblock if this statement starts it, else null