Remove 'classifier' method usages in tests

^KT-55624 In Progress

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/KotlinGradlePluginIT.kt

@@ -418,7 +418,7 @@ class KotlinGradleIT : KGPBaseTest() {
                 
                 task sourcesJar(type: Jar) {
                     from sourceSets.main.allSource
-                    classifier 'source'
+                    archiveClassifier = 'source'
                     duplicatesStrategy = 'fail' // fail in case of Java source duplication, see KT-17564
                 }
 

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsProject/libraryProject/build.gradle

@@ -21,7 +21,7 @@ dependencies {
 
 task jarSources(type: Jar) {
     from sourceSets.main.allSource
-    classifier = 'source'
+    archiveClassifier = 'source'
 }
 artifacts {
     implementation jarSources

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/kotlin2JsProjectWithTests/build.gradle

@@ -22,7 +22,7 @@ dependencies {
 
 task jarSources(type: Jar) {
     from sourceSets.main.allSource
-    classifier = 'source'
+    archiveClassifier = 'source'
 }
 artifacts {
     implementation jarSources