KT-57598 Run Kapt with K1 even when the compiler is run with K2

plugins/kapt3/kapt3-cli/testData/integration/fallback/ap/META-INF/services/javax.annotation.processing.Processor

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+apt.SampleApt

plugins/kapt3/kapt3-cli/testData/integration/fallback/ap/Processor.kt

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+package apt
+
+import javax.annotation.processing.*
+import javax.lang.model.SourceVersion
+import javax.lang.model.element.TypeElement
+import javax.tools.Diagnostic.Kind.*
+import javax.tools.StandardLocation
+
+annotation class Anno
+
+class SampleApt : AbstractProcessor() {
+    override fun process(annotations: Set<TypeElement>, roundEnv: RoundEnvironment): Boolean {
+        val writeKotlinFiles = processingEnv.options["kapt.test.writeKotlinFiles"] == "true"
+
+        for (element in roundEnv.getElementsAnnotatedWith(Anno::class.java)) {
+            val generatedSimpleName = element.simpleName.toString().capitalize()
+
+            val file = when (writeKotlinFiles) {
+                true -> processingEnv.filer.createResource(StandardLocation.SOURCE_OUTPUT, "generated", "$generatedSimpleName.kt")
+                false -> processingEnv.filer.createSourceFile("generated.$generatedSimpleName")
+            }
+
+            file.openWriter().use {
+                it.write("package generated;\npublic class $generatedSimpleName {}")
+            }
+        }
+
+        return true
+    }
+
+    override fun getSupportedOptions() = setOf("kapt.test.writeKotlinFiles")
+    override fun getSupportedSourceVersion() = SourceVersion.RELEASE_8
+    override fun getSupportedAnnotationTypes() = setOf("apt.Anno")
+}