odsign_e2e_tests: Drop Java 11-ism

Use Optional.isPresent() instead of Optional.isEmpty().

Bug: 193753166
Test: m
Change-Id: Ife11afa2310f9d78645354587e47ec98d21f07c5
diff --git a/test/odsign/test-src/com/android/tests/odsign/OnDeviceSigningHostTest.java b/test/odsign/test-src/com/android/tests/odsign/OnDeviceSigningHostTest.java
index 362e33d..78b1ac2 100644
--- a/test/odsign/test-src/com/android/tests/odsign/OnDeviceSigningHostTest.java
+++ b/test/odsign/test-src/com/android/tests/odsign/OnDeviceSigningHostTest.java
@@ -211,7 +211,7 @@
         int zygoteCount = 0;
         for (String zygoteName : ZYGOTE_NAMES) {
             final Optional<Set<String>> mappedArtifacts = getZygoteLoadedArtifacts(zygoteName);
-            if (mappedArtifacts.isEmpty()) {
+            if (!mappedArtifacts.isPresent()) {
                 continue;
             }
             verifyZygoteLoadedArtifacts(zygoteName, mappedArtifacts.get());