Speed up gradle configuration step.

This CL speeds up gradle configuration step (e.g. ./gradlew tasks)
by 10 seconds. We were buiding jacoco ant jar every time we configured
gradle during building the task graph. This CL makes it lazily
evaluated when task is actually run.

Test: ./gradlew tasks --scan
Change-Id: Ie1d4cc416fd1f41149b1b714ed63e1921c099db7
diff --git a/buildSrc/init.gradle b/buildSrc/init.gradle
index ee92488..3bd6d16 100644
--- a/buildSrc/init.gradle
+++ b/buildSrc/init.gradle
@@ -201,26 +201,29 @@
                             destinationDir file(project.distDir)
                             archiveName "${project.archivesBaseName}-${v.baseName}-allclasses.jar"
                         }
+
                         def jacocoAntConfig =
                                 project.configurations[JacocoPlugin.ANT_CONFIGURATION_NAME]
                         def jacocoAntArtifacts = jacocoAntConfig.resolvedConfiguration
                                 .resolvedArtifacts
-                        def version = jacocoAntArtifacts.find { "org.jacoco.ant".equals(it.name) }
-                                .moduleVersion.id.version
+
                         def collectJacocoAntPackages = project.tasks.create(
                                 name: "collectJacocoAntPackages",
                                 type: Jar) {
-                            from(jacocoAntArtifacts.collect { zipTree(it.getFile()) }) {
-                                // exclude all the signatures the jar might have
-                                exclude "META-INF/*.SF"
-                                exclude "META-INF/*.DSA"
-                                exclude "META-INF/*.RSA"
-                            }
+                            inputs.files project.configurations[JacocoPlugin.ANT_CONFIGURATION_NAME]
+                            from {
+                                jacocoAntArtifacts.collect{ zipTree(it.getFile()) }} {
+                                    // exclude all the signatures the jar might have
+                                    exclude "META-INF/*.SF"
+                                    exclude "META-INF/*.DSA"
+                                    exclude "META-INF/*.RSA"
+                                }
                             destinationDir file(project.distDir)
-                            archiveName "jacocoant-" + version + ".jar"
+                            archiveName "jacocoant.jar"
                         }
+
                         jarifyTask.dependsOn v.getJavaCompiler()
-                        v.assemble.dependsOn jarifyTask, collectJacocoAntPackages
+                        v.assemble.dependsOn jarifyTask , collectJacocoAntPackages
                     }
                 }