Don't mark record decls invalid when one of its methods is invalid, PR18284.

Don't mark record decls invalid when one of its methods is invalid, PR18284.

Without this patch, record decls with invalid out-of-line method delcs would
sometimes be marked invalid, but not always.  With this patch, they are
consistently never marked invalid.

(The code to do this was added in
http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20100809/033154.html
, but the test from that revision is still passing.)

As far as I can tell, this was the only place where a class was marked invalid
after its definition was complete.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@197848 91177308-0d34-0410-b5e6-96231b3b80d8