[flang][openacc] Resolve symbol in device, host and self clause

[flang][openacc] Resolve symbol in device, host and self clause

Some symbols were not resolved in the device, host and self clause
resulting in an `Internal: no symbol found` error.

This patch adds symbol resolution for these clauses.

Reviewed By: razvanlupusoru

Differential Revision: https://reviews.llvm.org/D153919