Fix UseAuto not transforming iterator when non-fully qualifiers are used and

using inline namespaces is specified.

UseAuto used to fail to transform iterators when using inline namespaces and
non-fully qualified types, relying on a using directive previously declared.
- This fix uses the already define isFromStdNamespace matcher.
- Fixed tests and added a new test using inline namespaces.
- Added CustomMatchers to reuse common matchers among transforms.

llvm-svn: 186327