Improve exemptions for CollectionUndefinedEquality.

Use SortedMap in place of TreeMap, and add SortedSet to the exemption list.

Context: #1634 (comment)

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=313469240

Author: eaftan

core/src/main/java/com/google/errorprone/bugpatterns/collectionincompatibletype/CollectionUndefinedEquality.java

@@ -57,7 +57,8 @@ public final class CollectionUndefinedEquality extends BugChecker
                   ImmutableList.of(
                       "java.util.IdentityHashMap",
                       "java.util.IdentityHashSet",
-                      "java.util.TreeMap")));
+                      "java.util.SortedMap",
+                      "java.util.SortedSet")));
 
   @Override
   public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {

core/src/test/java/com/google/errorprone/bugpatterns/collectionincompatibletype/CollectionUndefinedEqualityTest.java

@@ -71,4 +71,34 @@ public void treeMap_noFinding() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void sortedMap_noFinding() {
+    helper
+        .addSourceLines(
+            "Test.java",
+            "import java.util.Collection;",
+            "import java.util.SortedMap;",
+            "class Test {",
+            "  boolean foo(SortedMap<Collection<Integer>, Integer> xs, Collection<Integer> x) {",
+            "    return xs.containsKey(x);",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void sortedSet_noFinding() {
+    helper
+        .addSourceLines(
+            "Test.java",
+            "import java.util.Collection;",
+            "import java.util.SortedSet;",
+            "class Test {",
+            "  boolean foo(SortedSet<Collection<Integer>> xs, Collection<Integer> x) {",
+            "    return xs.contains(x);",
+            "  }",
+            "}")
+        .doTest();
+  }
 }