build: add missing @babel/generator bazel dep to fix //packages/localize/src/tools/test:test (#34974)

It's not clear how this ever worked (npm hoisting is a suspect though), but this dep is required because
one of the tests imports @babel/generator in the ts sources.

The lack of this dep is breaking builds on the master branch.

More discussion about this issue on Slack: https://angular-team.slack.com/archives/C07DT5M6V/p1579934766007500

PR Close #34974

packages/localize/src/tools/test/BUILD.bazel

@@ -11,6 +11,7 @@ ts_library(
         "//packages/compiler",
         "//packages/localize",
         "//packages/localize/src/tools",
+        "@npm//@babel/generator",
         "@npm//@babel/template",
         "@npm//@babel/types",
         "@npm//@types/babel__core",