Separate build-specific types and types inherent to Skylark.

--
MOS_MIGRATED_REVID=103374106
diff --git a/src/main/java/com/google/devtools/build/lib/packages/Package.java b/src/main/java/com/google/devtools/build/lib/packages/Package.java
index c78b6d0..41224e0 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/Package.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/Package.java
@@ -1272,9 +1272,9 @@
       for (Rule rule : rules) {
         AttributeMap attributes = NonconfigurableAttributeMapper.of(rule);
         if (rule.getRuleClass().equals("test_suite")
-            && attributes.get("tests", Type.LABEL_LIST).isEmpty()
-            && (!attributes.has("suites", Type.LABEL_LIST)
-                || attributes.get("suites", Type.LABEL_LIST).isEmpty())) {
+            && attributes.get("tests", BuildType.LABEL_LIST).isEmpty()
+            && (!attributes.has("suites", BuildType.LABEL_LIST)
+                || attributes.get("suites", BuildType.LABEL_LIST).isEmpty())) {
           rule.setAttributeValueByName("$implicit_tests", allTests);
         }
       }