fix(select): set value individually from ngModel

[kara]

• Please check if the PR fulfills these requirements
• The commit message follows our guidelines: https://github.com/angular/angular/blob/master/CONTRIBUTING.md#commit-message-format
• Tests for the changes have been added (for bug fixes / features)
• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)
  Fixes Select box option [value]'s not being set in NgFor without using NgModel #7975

[mary-poppins]

Merging PR #7978 on behalf of @alxhub to branch presubmit-alxhub-pr-7978.

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}