Build: Rework runtimeJar helper and drop redundant configuration

#KTI-559

libraries/tools/kotlin-gradle-plugin-test-utils-embeddable/build.gradle.kts

@@ -3,18 +3,12 @@
  * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
-
-import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
-import org.gradle.jvm.tasks.Jar
-
 description = "Shaded test jars from compiler for Gradle integration tests"
 
 plugins {
     `java-library`
 }
 
-val packedJars by configurations.creating
-
 val projectsToInclude = listOf(
     ":compiler:test-infrastructure-utils",
     ":compiler:tests-common",
@@ -25,15 +19,10 @@ val projectsToInclude = listOf(
 dependencies {
     for (projectName in projectsToInclude) {
         api(projectTests(projectName)) { isTransitive = false }
-        packedJars(projectTests(projectName)) { isTransitive = false }
+        embedded(projectTests(projectName)) { isTransitive = false }
     }
 
-    packedJars(intellijDep()) { includeJars("idea_rt") }
-
+    embedded(intellijDep()) { includeJars("idea_rt") }
 }
 
-runtimeJar(rewriteDepsToShadedCompiler(
-    tasks.register<ShadowJar>("shadowJar")  {
-        from(packedJars)
-    }
-))
+runtimeJar(rewriteDefaultJarDepsToShadedCompiler())