Don't apply lvalue-to-rvalue conversion in DefaultLValueConversion to

the expression that is passed to it if it has a function type or array
type

lvalue-to-rvalue conversion should only be applied to non-function,
non-array types, but clang was applying the conversion to discarded
value expressions of array types.

rdar://problem/61203170

Differential Revision: https://reviews.llvm.org/D78134