fix(@angular-devkit/build-angular): update babel to 7.8.7

[clydin]

Babel versions 7.8.0-7.8.6 contain a defect that can cause failures due to babel plugin changes (even in patch versions). Plugins are not pinned as they are deep transitive dependencies of the packages adjusted in this commit. This failure will prevent a newly generated project from building and can only be worked around by disabling differential loading.

Fixes: #17262

NOTE TO CARETAKER: pending status of ci/angular: merge status is incorrect and can be ignored. The two missing status checks do not exist on this branch.

[alan-agius4]

LGTM!

[ngbot]

I see that you just added the PR action: merge label, but the following checks are still failing:
     status "ci/angular: size" is failing
     status "ci/circleci: e2e-cli" is failing
     status "ci/circleci: e2e-cli-ivy" is failing
     status "ci/circleci: test-win" is failing
     missing required status "ci/circleci: test-large-ve"
     missing required status "ci/circleci: e2e-cli-ve"

If you want your PR to be merged, it has to pass all the CI checks.

If you can't get the PR to a green state due to flakes or broken master, please try rebasing to master and/or restarting the CI job. If that fails and you believe that the issue is not due to your change, please contact the caretaker and ask for help.

[googlebot]

All (the pull request submitter and all commit authors) CLAs are signed, but one or more commits were authored or co-authored by someone other than the pull request submitter.

We need to confirm that all authors are ok with their commits being contributed to this project. Please have them confirm that by leaving a comment that contains only @googlebot I consent. in this pull request.

Note to project maintainer: There may be cases where the author cannot leave a comment, or the comment is not properly detected as consent. In those cases, you can manually confirm consent of the commit author(s), and set the cla label to yes (if enabled on your project).

ℹ️ Googlers: Go here for more info.

[alan-agius4]

@googlebot I consent

[googlebot]

CLAs look good, thanks!

ℹ️ Googlers: Go here for more info.

[angular-automatic-lock-bot]

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