add 'isSafe' to FqNameUnsafe

compiler/frontend/src/org/jetbrains/jet/lang/resolve/name/FqName.java

@@ -62,7 +62,7 @@ public class FqName extends FqNameBase {
         }
     }
 
-    private static boolean isValidAfterUnsafeCheck(@NotNull String qualifiedName) {
+    /*package*/ static boolean isValidAfterUnsafeCheck(@NotNull String qualifiedName) {
         // TODO: There's a valid name with escape char ``
         return qualifiedName.indexOf('<') < 0;
     }

compiler/frontend/src/org/jetbrains/jet/lang/resolve/name/FqNameUnsafe.java

@@ -91,6 +91,13 @@ public class FqNameUnsafe extends FqNameBase {
         return fqName;
     }
 
+    public boolean isSafe() {
+        if (safe != null) {
+            return true;
+        }
+        return FqName.isValidAfterUnsafeCheck(getFqName());
+    }
+
     @NotNull
     public FqName toSafe() {
         if (safe != null) {