[flang] Allow redudant attributes on use-/host- associated names

Constraint C815 in F'2018 allows a name to acquire an attribute at
most once per scope.  For some attributes, the attribute may have
already been inherited, and the compiler was emitting a bogus error
message for a redundant application of the same attribute in another
scope.

Fixes https://github.com/llvm/llvm-project/issues/60274

Differential Revision: https://reviews.llvm.org/D150819