dart2js cps: Do not inline static async methods.

pkg/compiler/lib/src/cps_ir/type_propagation.dart

Index: pkg/compiler/lib/src/cps_ir/type_propagation.dart
diff --git a/pkg/compiler/lib/src/cps_ir/type_propagation.dart b/pkg/compiler/lib/src/cps_ir/type_propagation.dart
index b583dc49a4e828f7755580d2ce047abb7888cf18..493201f397869d45228db117788fbe6399bf04c4 100644
--- a/pkg/compiler/lib/src/cps_ir/type_propagation.dart
+++ b/pkg/compiler/lib/src/cps_ir/type_propagation.dart
@@ -1878,6 +1878,11 @@ class TransformingVisitor extends DeepRecursiveVisitor {
     // The target might not have an AST, for example if it deferred.
     if (!node.target.hasNode) return false;
 
+    if (node.target.asyncMarker != AsyncMarker.SYNC) {
+      // Inlining of async/sync*/async* methods is currently not supported.
+      return false;
+    }
+
     // True if an expression is non-expansive, in the sense defined by this
     // predicate.
     bool isNonExpansive(ast.Expression expr) {