build: bazel not working on windows workaround (#15484)

Recently we updated our Bazel setup to Angular V8 beta. With that change
the Sass dependencies took precedence and now fetch the skylib repository
using the `git_repository` bazel rule. Unfortunately this rule does not always
work as expected in Windows (e.g. when used within Git Bash). Until Bazel
drops the dependency on bash, we should make sure that we fetch skylib
through the `http_archive` rule (which works on windows). Skylib will be
transitively brought in by the `rules_webtesting` repository.

WORKSPACE

@@ -52,14 +52,6 @@ ts_setup_workspace()
 load("@npm_bazel_karma//:package.bzl", "rules_karma_dependencies")
 rules_karma_dependencies()
 
-# Fetch transitive dependencies which are needed to use the Sass rules.
-load("@io_bazel_rules_sass//:package.bzl", "rules_sass_dependencies")
-rules_sass_dependencies()
-
-# Setup the Sass rule repositories.
-load("@io_bazel_rules_sass//:defs.bzl", "sass_repositories")
-sass_repositories()
-
 # Setup web testing. We need to setup a browser because the web testing rules for TypeScript need
 # a reference to a registered browser (ideally that's a hermetic version of a browser)
 load("@io_bazel_rules_webtesting//web:repositories.bzl", "web_test_repositories")
@@ -68,6 +60,14 @@ web_test_repositories()
 load("@npm_bazel_karma//:browser_repositories.bzl", "browser_repositories")
 browser_repositories()
 
+# Fetch transitive dependencies which are needed to use the Sass rules.
+load("@io_bazel_rules_sass//:package.bzl", "rules_sass_dependencies")
+rules_sass_dependencies()
+
+# Setup the Sass rule repositories.
+load("@io_bazel_rules_sass//:defs.bzl", "sass_repositories")
+sass_repositories()
+
 # Temporarily add Angular sources and its dependencies to consume the ts_api_guardian,
 # remote-build-execution, and protractor stuff.
 # TODO(jelbourn): remove this once we can do all the same stuff via @npm//@angular