[flang] Semantic checks for bad usage of whole assumed-size arrays

The semantics pass currently checks for several constraints
that apply to the use of whole assumed-size arrays in various
contexts, but C1002 wasn't really implemented.  This patch
implements C1002 by disallowing the use of whole assumed-size
arrays in expressions and variables unless specifically
allowed by the context.  This centralizes the error reporting,
which has been improved with a link to the array's declaration.

Differential revision: https://reviews.llvm.org/D88691