Fix Gradle task input annotations for Gradle 5.5 checks

* Interface and abstract properties are now checked, too.
  For them, copy the @Input/@Internal annotations from the
  implementations (luckily, they were all consistent).

* Annotating a private property without a public accessor is not not
  allowed. Remove one such annotation.

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/dsl/KotlinCompile.kt

@@ -18,6 +18,8 @@ package org.jetbrains.kotlin.gradle.dsl
 
 import groovy.lang.Closure
 import org.gradle.api.Task
+import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.Internal
 
 interface KotlinJsCompile : KotlinCompile<KotlinJsOptions>
 
@@ -26,8 +28,10 @@ interface KotlinJvmCompile : KotlinCompile<KotlinJvmOptions>
 interface KotlinCommonCompile : KotlinCompile<KotlinMultiplatformCommonOptions>
 
 interface KotlinJsDce : Task {
+    @get:Internal
     val dceOptions: KotlinJsDceOptions
 
+    @get:Input
     val keep: MutableList<String>
 
     fun dceOptions(fn: KotlinJsDceOptions.() -> Unit) {

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/dukat/DukatTask.kt

@@ -37,6 +37,7 @@ abstract class AbstractDukatTask : AbstractTask(), RequiresNpmDependencies {
     /**
      * Collection of d.ts files
      */
+    @get:Internal
     abstract val dTsFiles: List<File>
 
     /**

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/native/tasks/KotlinNativeTasks.kt

@@ -92,6 +92,7 @@ abstract class AbstractKotlinNativeCompile : AbstractCompile(), KotlinCompile<Ko
         targetCompatibility = "1.6"
     }
 
+    @get:Internal
     abstract val compilation: KotlinNativeCompilation
 
     // region inputs/outputs
@@ -104,6 +105,7 @@ abstract class AbstractKotlinNativeCompile : AbstractCompile(), KotlinCompile<Ko
     @get:Input
     abstract val debuggable: Boolean
 
+    @get:Internal
     abstract val baseName: String
 
     // Inputs and outputs

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

@@ -41,7 +41,6 @@ open class KotlinTestReport : TestReport() {
     @Internal
     val testTasks = mutableListOf<AbstractTestTask>()
 
-    @Internal
     private var parent: KotlinTestReport? = null
 
     @Internal