LanguageSpecificCheckValid for imports.

Full CheckValid requires too much information, but
LanguageSpecificCheckValid appears not to, and it can cause some better
error messages (specifically, before, aidl was aborting if cpp_header
wasn't specified on a parcelable that was depended on by an interface
being compiled).

Bug: 194846019
Test: TH
Change-Id: I09c4291bf44bb86ac34f7bd74655c7409da597d5
2 files changed