[modules] Fix deserialization cycle when loading a tag declaration with a typedef name for linkage purposes. When loading the type, delay loading its typedef until we've finished loading and merging the type. In its place, save out the name of the typedef, which we need for merging purposes.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@216806 91177308-0d34-0410-b5e6-96231b3b80d8
Cleanup test.

This should make it easier to add more tests to this file.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@216807 91177308-0d34-0410-b5e6-96231b3b80d8