Don't allow duplicates in premium/reserved lists

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=148458642

javatests/google/registry/model/registry/label/PremiumListTest.java

@@ -273,6 +273,18 @@ public class PremiumListTest {
     }
   }
 
+  @Test
+  public void testParse_cannotIncludeDuplicateLabels() {
+    thrown.expect(
+        IllegalStateException.class,
+        "List 'tld' cannot contain duplicate labels. Dupes (with counts) were: [lol x 2]");
+    PremiumList.get("tld")
+        .get()
+        .parse(
+            ImmutableList.of(
+                "lol,USD 100", "rofl,USD 90", "paper,USD 80", "wood,USD 70", "lol,USD 200"));
+  }
+
   /** Persists a premium list with a specified number of nonsense entries. */
   private PremiumList persistHumongousPremiumList(String name, int size) {
     String[] entries = new String[size];

javatests/google/registry/model/registry/label/ReservedListTest.java

@@ -291,6 +291,21 @@ public class ReservedListTest {
             .build());
   }
 
+  @Test
+  public void testParse_cannotIncludeDuplicateLabels() {
+    ReservedList rl = new ReservedList.Builder().setName("blah").build();
+    thrown.expect(
+        IllegalStateException.class,
+        "List 'blah' cannot contain duplicate labels. Dupes (with counts) were: [lol x 2]");
+    rl.parse(
+        ImmutableList.of(
+            "lol,FULLY_BLOCKED",
+            "rofl,FULLY_BLOCKED",
+            "paper,FULLY_BLOCKED",
+            "wood,FULLY_BLOCKED",
+            "lol,FULLY_BLOCKED"));
+  }
+
   /** Gets the name of a reserved list. */
   public static final Function<Key<ReservedList>, String> GET_NAME_FUNCTION =
       new Function<Key<ReservedList>, String>() {