[clang] Fix noderef for array member of deref expr
Committing on behalf of thejh (Jann Horn).
Given an attribute((noderef)) pointer "p" to the struct
struct s { int a[2]; };
ensure that the following expressions are treated the same way by the
noderef logic:
p->a
(*p).a
Until now, the first expression would be treated correctly (nothing is
added to PossibleDerefs because CheckMemberAccessOfNoDeref() bails out
on array members), but the second expression would incorrectly warn
because "*p" creates a PossibleDerefs entry.
Handle this case the same way as for the AddrOf operator.
Differential Revision: https://reviews.llvm.org/D92140