Enable non-function type aliases by default in 2.13.

TEST=language/nonfunction-type-aliases

Change-Id: Ifff4e838fbfc4f71e2d990e1f1f8a67b987adf91
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/192948
Commit-Queue: Leaf Petersen <leafp@google.com>
Reviewed-by: Erik Ernst <eernst@google.com>

runtime/vm/experimental_features.cc

@@ -18,7 +18,7 @@ namespace dart {
 
 bool GetExperimentalFeatureDefault(ExperimentalFeature feature) {
   constexpr bool kFeatureValues[] = {
-      true, true, true, true, true, true,
+      true, true, true, true, true, true, true,
   };
   ASSERT(static_cast<size_t>(feature) < ARRAY_SIZE(kFeatureValues));
   return kFeatureValues[static_cast<int>(feature)];
@@ -26,9 +26,10 @@ bool GetExperimentalFeatureDefault(ExperimentalFeature feature) {
 
 const char* GetExperimentalFeatureName(ExperimentalFeature feature) {
   constexpr const char* kFeatureNames[] = {
-      "non-nullable",         "extension-methods",
-      "constant-update-2018", "control-flow-collections",
-      "set-literals",         "spread-collections",
+      "nonfunction-type-aliases", "non-nullable",
+      "extension-methods",        "constant-update-2018",
+      "control-flow-collections", "set-literals",
+      "spread-collections",
   };
   ASSERT(static_cast<size_t>(feature) < ARRAY_SIZE(kFeatureNames));
   return kFeatureNames[static_cast<int>(feature)];

runtime/vm/experimental_features.h

@@ -14,6 +14,7 @@
 namespace dart {
 
 enum class ExperimentalFeature {
+  nonfunction_type_aliases,
   non_nullable,
   extension_methods,
   constant_update_2018,