[flang] Allow exterior branch to outermost WHERE construct statement

The labels of WHERE constructs were being created within the scope of
the construct, not the scope of its parent, leading to incorrect error
messages for branches to that label.

Differential Revision: https://reviews.llvm.org/D113696

Author: klausler

flang/lib/Semantics/resolve-labels.cpp

@@ -229,7 +229,8 @@ class ParseTreeAnalyzer {
     using LabeledConstructStmts = std::tuple<parser::AssociateStmt,
         parser::BlockStmt, parser::ChangeTeamStmt, parser::CriticalStmt,
         parser::IfThenStmt, parser::NonLabelDoStmt, parser::SelectCaseStmt,
-        parser::SelectRankStmt, parser::SelectTypeStmt>;
+        parser::SelectRankStmt, parser::SelectTypeStmt,
+        parser::WhereConstructStmt>;
     using LabeledConstructEndStmts = std::tuple<parser::EndAssociateStmt,
         parser::EndBlockStmt, parser::EndChangeTeamStmt,
         parser::EndCriticalStmt, parser::EndDoStmt, parser::EndForallStmt,