[Concurrency] unguard nonisolated(unsafe) attribute from GlobalConcurrency experimental feature

(cherry picked from commit d319404)

Author: sophiapoirier

lib/ASTGen/Sources/ASTGen/SourceFile.swift

@@ -36,7 +36,6 @@ extension Parser.ExperimentalFeatures {
       }
     }
     mapFeature(.ThenStatements, to: .thenStatements)
-    mapFeature(.GlobalConcurrency, to: .globalConcurrency)
   }
 }
 

lib/Parse/ParseDecl.cpp

@@ -5344,8 +5344,7 @@ bool Parser::isStartOfSwiftDecl(bool allowPoundIfAttributes,
   }
 
   // If this is 'nonisolated', check to see if it is valid.
-  if (Context.LangOpts.hasFeature(Feature::GlobalConcurrency) &&
-      Tok.isContextualKeyword("nonisolated") && Tok2.is(tok::l_paren) &&
+  if (Tok.isContextualKeyword("nonisolated") && Tok2.is(tok::l_paren) &&
       isParenthesizedNonisolated(*this)) {
     BacktrackingScope backtrack(*this);
     consumeToken(tok::identifier);

lib/Sema/TypeCheckAttr.cpp

@@ -6594,14 +6594,11 @@ void AttributeChecker::visitNonisolatedAttr(NonisolatedAttr *attr) {
   auto dc = D->getDeclContext();
 
   if (auto var = dyn_cast<VarDecl>(D)) {
-    const bool isUnsafe =
-        attr->isUnsafe() && Ctx.LangOpts.hasFeature(Feature::GlobalConcurrency);
-
     // stored properties have limitations as to when they can be nonisolated.
     if (var->hasStorage()) {
       // 'nonisolated' can not be applied to mutable stored properties unless
       // qualified as 'unsafe'.
-      if (var->supportsMutation() && !isUnsafe) {
+      if (var->supportsMutation() && !attr->isUnsafe()) {
         diagnoseAndRemoveAttr(attr, diag::nonisolated_mutable_storage);
         return;
       }
@@ -6645,7 +6642,7 @@ void AttributeChecker::visitNonisolatedAttr(NonisolatedAttr *attr) {
 
     // nonisolated can not be applied to local properties unless qualified as
     // 'unsafe'.
-    if (dc->isLocalContext() && !isUnsafe) {
+    if (dc->isLocalContext() && !attr->isUnsafe()) {
       diagnoseAndRemoveAttr(attr, diag::nonisolated_local_var);
       return;
     }

lib/Sema/TypeCheckConcurrency.cpp

@@ -2813,8 +2813,7 @@ namespace {
         return false;
 
       if (auto attr = value->getAttrs().getAttribute<NonisolatedAttr>();
-          ctx.LangOpts.hasFeature(Feature::GlobalConcurrency) && attr &&
-          attr->isUnsafe()) {
+          attr && attr->isUnsafe()) {
         return false;
       }
 
@@ -3282,8 +3281,7 @@ namespace {
         }
 
         if (auto attr = var->getAttrs().getAttribute<NonisolatedAttr>();
-            ctx.LangOpts.hasFeature(Feature::GlobalConcurrency) && attr &&
-            attr->isUnsafe()) {
+            attr && attr->isUnsafe()) {
           return false;
         }