Arrange for the Gradle integration test to run in the install phase.

I am not sure how this test worked before. I think it happened to work as a side effect of other integration tests installing the `HEAD-SNAPSHOT` artifacts, which we stopped doing in #1451. It happens that we noticed the breakage with a Dependabot [PR](#1452) to update `gradle-test-kit`, but I think the CI was already broken.

Anyway, the Gradle test assumes it can depend on the artifacts for the current AutoValue version, and those are only available in the `install` phase.

By following the Maven convention whereby regular unit tests are called `FooTest` and integration tests are called `FooIT`, we get the right tests run in the right phases without having to specify `<include>` and the like.

RELNOTES=n/a
PiperOrigin-RevId: 511051082

value/src/it/functional/pom.xml

@@ -183,12 +183,26 @@
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-surefire-plugin</artifactId>
         <version>2.22.2</version>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-failsafe-plugin</artifactId>
+        <version>2.22.2</version>
         <configuration>
           <systemPropertyVariables>
             <autoValueVersion>${project.version}</autoValueVersion>
           </systemPropertyVariables>
         </configuration>
-      </plugin>
+        <executions>
+          <execution>
+            <phase>install</phase>
+            <goals>
+              <goal>integration-test</goal>
+              <goal>verify</goal>
+            </goals>
+          </execution>
+        </executions>
+     </plugin>
     </plugins>
   </build>
 

value/src/it/functional/src/test/java/com/google/auto/value/CompileWithEclipseTest.java

@@ -70,7 +70,7 @@ public static void setSourceRoot() {
           "AutoValueNotEclipseTest.java",
           "CompileWithEclipseTest.java",
           "CustomFieldSerializerTest.java",
-          "GradleTest.java",
+          "GradleIT.java",
 
           // AutoBuilder sometimes needs to generate a .class file for Kotlin that is used in the
           // rest of compilation, and Eclipse doesn't seem to handle that well. Presumably not many

value/src/it/functional/src/test/java/com/google/auto/value/GradleTest.java → value/src/it/functional/src/test/java/com/google/auto/value/GradleIT.java

@@ -38,7 +38,7 @@
 import org.junit.runners.JUnit4;
 
 @RunWith(JUnit4.class)
-public class GradleTest {
+public class GradleIT {
   @Rule public TemporaryFolder fakeProject = new TemporaryFolder();
 
   private static final String BUILD_GRADLE_TEXT =