Parse: Use InInactiveClauseEnvironment instead of looking at the Scope

We have two ways of knowing if we're inside of an inactive #if clause.
Refactor the only two places that called getScopeInfo().isInactiveConfigBlock()
to check InInactiveClauseEnvironment instead.

This removes the last remaining usage of Scope that's not related to
parse-time name lookup.

Author: slavapestov

lib/Parse/ParseDecl.cpp

@@ -3813,7 +3813,7 @@ void Parser::setLocalDiscriminator(ValueDecl *D) {
     return;
 
   if (auto TD = dyn_cast<TypeDecl>(D))
-    if (!getScopeInfo().isInactiveConfigBlock())
+    if (!InInactiveClauseEnvironment)
       SF.LocalTypeDecls.insert(TD);
 
   const Identifier name = D->getBaseIdentifier();

lib/Parse/ParseIfConfig.cpp

@@ -635,7 +635,7 @@ ParserResult<IfConfigDecl> Parser::parseIfConfig(
       // Don't evaluate if it's in '-parse' mode, etc.
       shouldEvaluatePoundIfDecls() &&
       // If it's in inactive #if ... #endif block, there's no point to do it.
-      !getScopeInfo().isInactiveConfigBlock() &&
+      !InInactiveClauseEnvironment &&
       // If this directive contains code completion location, 'isActive' is
       // determined solely by which block has the completion token.
       !codeCompletionClauseLoc.isValid();