Fix identification of external synthetics in tests.

Change-Id: Ib37515ed32ae619b0d668ad4ef350691d2fffc1c
diff --git a/src/test/java/com/android/tools/r8/synthesis/SyntheticItemsTestUtils.java b/src/test/java/com/android/tools/r8/synthesis/SyntheticItemsTestUtils.java
index 804c5f8..5977b9a 100644
--- a/src/test/java/com/android/tools/r8/synthesis/SyntheticItemsTestUtils.java
+++ b/src/test/java/com/android/tools/r8/synthesis/SyntheticItemsTestUtils.java
@@ -75,9 +75,7 @@
 
   public static boolean isExternalSynthetic(ClassReference reference) {
     for (SyntheticKind kind : SyntheticKind.values()) {
-      if (kind == SyntheticKind.RECORD_TAG
-          || kind == SyntheticKind.EMULATED_INTERFACE_MARKER_CLASS
-          || kind == SyntheticKind.RETARGET_STUB) {
+      if (kind.isGlobal()) {
         continue;
       }
       if (kind.isFixedSuffixSynthetic) {