Revert "refactor(BaseInjector): remove recursion from getInstanceByKey"

This reverts commit 68fc32d7913078e6a5c5d0bc8dae80aad8cd4125.
Revert "perf(injector): inlined getProviderWithInjector"

This reverts commit d2a38b542fd773ec937ca8413fa388e30a58daa3.

This commit tickled a dart2js bug in Dart 1.5, reverting until 1.6 is
stable.
chore(pubspec): Release 1.2.2