[flang][OpenMP] Make Symbol::OmpFlagToClauseName static (#113586)

It doesn't need the Symbol object for anything.

Author: kparzysz

flang/include/flang/Semantics/symbol.h

@@ -778,7 +778,7 @@ class Symbol {
   void set_offset(std::size_t offset) { offset_ = offset; }
   // Give the symbol a name with a different source location but same chars.
   void ReplaceName(const SourceName &);
-  std::string OmpFlagToClauseName(Flag ompFlag);
+  static std::string OmpFlagToClauseName(Flag ompFlag);
 
   // Does symbol have this type of details?
   template <typename D> bool has() const {

flang/lib/Semantics/resolve-directives.cpp

@@ -2320,7 +2320,7 @@ void OmpAttributeVisitor::ResolveOmpObject(
               if (auto *symbol{ResolveOmp(*name, ompFlag, currScope())}) {
                 auto checkExclusivelists =
                     [&](const Symbol *symbol1, Symbol::Flag firstOmpFlag,
-                        Symbol *symbol2, Symbol::Flag secondOmpFlag) {
+                        const Symbol *symbol2, Symbol::Flag secondOmpFlag) {
                       if ((symbol1->test(firstOmpFlag) &&
                               symbol2->test(secondOmpFlag)) ||
                           (symbol1->test(secondOmpFlag) &&
@@ -2330,9 +2330,8 @@ void OmpAttributeVisitor::ResolveOmpObject(
                             "appear on both %s and %s "
                             "clauses on a %s construct"_err_en_US,
                             symbol2->name(),
-                            const_cast<Symbol *>(symbol1)->OmpFlagToClauseName(
-                                firstOmpFlag),
-                            symbol2->OmpFlagToClauseName(secondOmpFlag),
+                            Symbol::OmpFlagToClauseName(firstOmpFlag),
+                            Symbol::OmpFlagToClauseName(secondOmpFlag),
                             parser::ToUpperCaseLetters(
                                 llvm::omp::getOpenMPDirectiveName(
                                     GetContext().directive)