More lazy API usage in our build (#9766)

* Use lazy API in publish

* Use lazy API in test-suites

Author: sarahchen6

gradle/publish.gradle

@@ -22,7 +22,7 @@ publishing {
   publications {
     maven(MavenPublication) { MavenPublication publication ->
       if (project.plugins.hasPlugin('com.gradleup.shadow')) {
-        publication.artifact(project.tasks.shadowJar)
+        publication.artifact(project.tasks.named("shadowJar"))
 
         // Required by Maven Central:
         publication.artifact sourcesJar

gradle/test-suites.gradle

@@ -57,8 +57,8 @@ ext.addTestSuiteExtendingForDir = { testSuiteName, parentSuiteName, dirName ->
   }
 
   tasks.register("${testSuiteName}Jar", Jar) {
-    dependsOn(tasks.named("${testSuiteName}Classes").get())
-    from(sourceSets.named(testSuiteName).get().output)
+    dependsOn(tasks.named("${testSuiteName}Classes"))
+    from(sourceSets.named(testSuiteName).map { it.output })
     archiveClassifier = testSuiteName
   }