Kapt3: Always write Kotlin stubs to .java files, and make javac always parse them from source files, not from JCTree (in order to support incremental compilation).

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/internal/Kapt3KotlinGradleSubplugin.kt

@@ -180,10 +180,10 @@ class Kapt3KotlinGradleSubplugin : KotlinGradleSubplugin<KotlinCompile> {
         }
 
         pluginOptions += SubpluginOption("useLightAnalysis", "${kaptExtension.useLightAnalysis}")
+        pluginOptions += SubpluginOption("stubs", getKaptStubsDir(project, sourceSetName).canonicalPath)
 
         if (project.hasProperty(VERBOSE_OPTION_NAME) && project.property(VERBOSE_OPTION_NAME) == "true") {
             pluginOptions += SubpluginOption("verbose", "true")
-            pluginOptions += SubpluginOption("stubs", getKaptStubsDir(project, sourceSetName).canonicalPath)
         }
     }