build: clean up references to old master branch (#45856)

Cleans up all references to the `master` branch we renamed to
`main` across Angular.

PR Close #45856

.circleci/config.yml

@@ -64,8 +64,6 @@ var_10: &only_on_main_branch
     branches:
       only:
         - main
-        # TODO(BRANCH_RENAME_CLEANUP): remove
-        - master
 
 # Filter to run a job on all releasable branches.
 var_11: &only_release_branches
@@ -73,8 +71,6 @@ var_11: &only_release_branches
     branches:
       only:
         - main
-        # TODO(BRANCH_RENAME_CLEANUP): remove
-        - master
         - /\d+\.\d+\.x/
 
 # CircleCI orbs
@@ -308,7 +304,7 @@ jobs:
           path: dist/bin/packages/core/test/bundling/todo/bundle.min.js.br
           destination: core/todo/bundle.br
 
-  # NOTE: This is currently limited to master builds only. See the `monitoring` configuration.
+  # NOTE: This is currently limited to main builds only. See the `monitoring` configuration.
   saucelabs:
     executor:
       name: default-executor

.circleci/rebase-pr.js

@@ -101,14 +101,6 @@ function getRefFromBranchList(gitOutput) {
       return 1;
     }
 
-    // TODO(BRANCH_RENAME_CLEANUP): remove
-    if (a === 'master') {
-      return -1;
-    }
-    if (b === 'master') {
-      return 1;
-    }
-
     const aIsSemver = semverRegex.test(a);
     const bIsSemver = semverRegex.test(b);
     if (aIsSemver && bIsSemver) {