makeForTest(test) {
    const context = this.loopContext;
    const forkContext = this.forkContext;
    const endOfInitSegments = forkContext.head;
    const testSegments = forkContext.makeNext(-1, -1);

    // Update state.
    context.test = test;
    context.endOfInitSegments = endOfInitSegments;
    context.continueDestSegments = context.testSegments = testSegments;
    forkContext.replaceHead(testSegments);
  }
Makes a code path segment for the test part of a ForStatement.
@param {boolean|undefined} test The test value (only when constant).
@returns {void}