[lldb][AST] fix declaration context passed to parameter vars

It needs to be the function declaration that the parameter belongs to,
   not the context of that function.

Author: temyurchenko

lldb/source/Plugins/ExpressionParser/Clang/NameSearchContext.cpp

@@ -98,10 +98,9 @@ clang::NamedDecl *NameSearchContext::AddFunDecl(const CompilerType &type,
     for (ArgIndex = 0; ArgIndex < NumArgs; ++ArgIndex) {
       QualType arg_qual_type(func_proto_type->getParamType(ArgIndex));
 
-      parm_var_decls.push_back(
-          ParmVarDecl::Create(ast, const_cast<DeclContext *>(context),
-                              SourceLocation(), SourceLocation(), nullptr,
-                              arg_qual_type, nullptr, SC_Static, nullptr));
+      parm_var_decls.push_back(ParmVarDecl::Create(
+          ast, func_decl, SourceLocation(), SourceLocation(), nullptr,
+          arg_qual_type, nullptr, SC_Static, nullptr));
     }
 
     func_decl->setParams(ArrayRef<ParmVarDecl *>(parm_var_decls));