Flip around assertion in SdkExtensionsTest

The assertion was the wrong way around before, making a failure
more difficult to understand (I didn't know about the isIn assert).

Previously...
        STACKTRACE:
        expected to contain: 3
        but was            : [2]

Now...
        STACKTRACE:
        expected any of: [2]
        but was        : 3

Test: atest SdkExtensionTest
Change-Id: I829e5010750aea28f7050caea0fa614affb01493
diff --git a/javatests/com/android/os/ext/SdkExtensionsTest.java b/javatests/com/android/os/ext/SdkExtensionsTest.java
index 29f570b..86909bd 100644
--- a/javatests/com/android/os/ext/SdkExtensionsTest.java
+++ b/javatests/com/android/os/ext/SdkExtensionsTest.java
@@ -30,7 +30,7 @@
 public class SdkExtensionsTest extends TestCase {
 
     private static void assertCorrectVersion(int version) throws Exception {
-        assertThat(ALLOWED_VERSIONS_CTS).contains(version);
+        assertThat(version).isIn(ALLOWED_VERSIONS_CTS);
     }
 
     private static void assertCorrectVersion(boolean expected, int version) throws Exception {