A filename can be remapped with a header map to point to a framework
header and we can find the corresponding framework without the header.
But if the original filename doesn't have a remapped framework name,
we'll fail to find its location and will dereference a null pointer
during diagnostics emission.
Fix by tracking remappings better and emit the note only if a framework
is found before any of the remappings.
rdar://problem/48883447
Reviewers: arphaman, erik.pilkington, jkorous
Reviewed By: arphaman
Subscribers: dexonsmith, cfe-commits
Differential Revision: https://reviews.llvm.org/D61707
llvm-svn: 361779
e32ff09685