[Test] Move KotlinAgainstKotlin tests under BlackBoxCodegen tests

compiler/testData/codegen/box/compileKotlinAgainstKotlin/fir/IncrementalCompilerRunner.kt

@@ -0,0 +1,26 @@
+// TARGET_BACKEND: JVM
+// MODULE: lib
+// FILE: A.kt
+// WITH_RUNTIME
+
+abstract class IncrementalCompilerRunner<T>(
+    private val workingDir: String,
+    val fail: Boolean,
+    val output: Collection<String> = emptyList()
+) {
+    fun res(res: T? = null): String = (res as? String) ?: (if (fail) "FAIL" else workingDir)
+}
+
+class IncrementalJsCompilerRunner(
+    private val workingDir: String,
+    fail: Boolean = true
+) : IncrementalCompilerRunner<String>(workingDir, fail) {
+}
+
+// MODULE: main(lib)
+// FILE: B.kt
+
+fun box(): String {
+    val runner = IncrementalJsCompilerRunner(workingDir = "OK", fail = false)
+    return runner.res()
+}