Move AccountGroup#isInternalGroup(UUID) into UUID class

Change-Id: I8475772f292d4917f90898f7fa16ddfd18e44ac8

java/com/google/gerrit/entities/AccountGroup.java

diff --git a/java/com/google/gerrit/entities/AccountGroup.java b/java/com/google/gerrit/entities/AccountGroup.java
index b6da194..0b2a346 100644
--- a/java/com/google/gerrit/entities/AccountGroup.java
+++ b/java/com/google/gerrit/entities/AccountGroup.java
@@ -54,6 +54,11 @@
       return uuid();
     }
 
+    /** @return true if the UUID is for a group managed within Gerrit. */
+    public boolean isInternalGroup() {
+      return get().matches("^[0-9a-f]{40}$");
+    }
+
     /** Parse an {@link AccountGroup.UUID} out of a string representation. */
     public static UUID parse(String str) {
       return AccountGroup.uuid(KeyUtil.decode(str));
@@ -92,11 +97,6 @@
     }
   }
 
-  /** @return true if the UUID is for a group managed within Gerrit. */
-  public static boolean isInternalGroup(AccountGroup.UUID uuid) {
-    return uuid.get().matches("^[0-9a-f]{40}$");
-  }
-
   public static Id id(int id) {
     return new AutoValue_AccountGroup_Id(id);
   }

java/com/google/gerrit/server/account/GroupIncludeCacheImpl.java

diff --git a/java/com/google/gerrit/server/account/GroupIncludeCacheImpl.java b/java/com/google/gerrit/server/account/GroupIncludeCacheImpl.java
index 7883b11..27fde83 100644
--- a/java/com/google/gerrit/server/account/GroupIncludeCacheImpl.java
+++ b/java/com/google/gerrit/server/account/GroupIncludeCacheImpl.java
@@ -125,7 +125,7 @@
       logger.atFine().log("Evict parent groups of %s", groupId.get());
       parentGroups.invalidate(groupId);
 
-      if (!AccountGroup.isInternalGroup(groupId)) {
+      if (!groupId.isInternalGroup()) {
         logger.atFine().log("Evict external group %s", groupId.get());
         external.invalidate(EXTERNAL_NAME);
       }

java/com/google/gerrit/server/group/db/Groups.java

diff --git a/java/com/google/gerrit/server/group/db/Groups.java b/java/com/google/gerrit/server/group/db/Groups.java
index 2925cb3..7a1b351 100644
--- a/java/com/google/gerrit/server/group/db/Groups.java
+++ b/java/com/google/gerrit/server/group/db/Groups.java
@@ -124,8 +124,7 @@
           getGroupFromNoteDb(allUsersName, allUsersRepo, internalGroup.getUUID());
       group.map(InternalGroup::getSubgroups).ifPresent(allSubgroups::addAll);
     }
-    return allSubgroups.build().stream()
-        .filter(groupUuid -> !AccountGroup.isInternalGroup(groupUuid));
+    return allSubgroups.build().stream().filter(groupUuid -> !groupUuid.isInternalGroup());
   }
 
   /**