AAPT2: Fix overzealous AndroidManifest fully qualified class names

ManifestFixer would go and fully qualify all elements with the attribute
'android:name', which is not correct, especially for cases like

  <uses-split android:name="foo" />

Test: make aapt2_tests
Change-Id: I4bea2550d0025179d2d48dca8c64e0cbf4451e99