Add test for PASS opcode

Bug: 320198097
Test: TH
Change-Id: I8af6f2606c7da77fa47603324600e87d68976635

tests/unit/src/android/net/apf/ApfTest.java

diff --git a/tests/unit/src/android/net/apf/ApfTest.java b/tests/unit/src/android/net/apf/ApfTest.java
index 5c6a906..37b9060 100644
--- a/tests/unit/src/android/net/apf/ApfTest.java
+++ b/tests/unit/src/android/net/apf/ApfTest.java
@@ -263,6 +263,12 @@
         ApfV4Generator gen = new ApfV4Generator(MIN_APF_VERSION);
         assertPass(gen);
 
+        // Test pass opcode
+        gen = new ApfV4Generator(MIN_APF_VERSION);
+        gen.addPass();
+        gen.addJump(DROP_LABEL);
+        assertPass(gen);
+
         // Test jumping to pass label.
         gen = new ApfV4Generator(MIN_APF_VERSION);
         gen.addJump(PASS_LABEL);