[flang] Ensure use of ObjectEntityDetails for data objects

A symbol is created with EntityDetails if we don't know whether it is a
procedure or data object. At the end of the specification part, if we
don't know it's a procedure then it must be an object, so convert it
then. So after name resolution there should be no symbols with
EntityDetails.

Also, a couple of small fixes:
- need to visit sub-nodes of shape specs so that any names get resolved
- don't report an error for an array element mis-parsed as a call

Original-commit: flang-compiler/f18@0effecd2252488455b1d2f0c86dc3dc00d37f483
Reviewed-on: https://github.com/flang-compiler/f18/pull/177
Tree-same-pre-rewrite: false