pushTryContext(hasFinalizer) {
    this.tryContext = {
      upper: this.tryContext,
      position: 'try',
      hasFinalizer,

      returnedForkContext: hasFinalizer
        ? ForkContext.newEmpty(this.forkContext)
        : null,

      thrownForkContext: ForkContext.newEmpty(this.forkContext),
      lastOfTryIsReachable: false,
      lastOfCatchIsReachable: false,
    };
  }
Creates a context object of TryStatement and stacks it.
@param {boolean} hasFinalizer `true` if the try statement has a
  `finally` block.
@returns {void}