[flang] Address OpenACC name resolution gaps (#164313)

Some OpenACC parsers aren't filling in the "source" data members of
parse tree nodes, or not doing so correctly; and some of those nodes are
not adding their source data members to the source ranges of the current
scope when being visited in name resolution, which causes
SemanticsContext::FindScope() to misidentify the current scope in
directive resolution when creating contexts. Further, the name
resolution for a "use_device" clause isn't walking its subtrees, so some
parser::Name nodes are not being resolved to Symbols.

Fix these problems, and clean up resolve-directives.cpp a bit, since
most Name nodes don't need to have their symbol table pointers updated
now.

0 files changed, 0 insertions, 0 deletions