Remove source annotations when copy class with kapt2

Writing source annotations enables incremental compilation for kapt2.
However they are not needed in bytecode, so we remove them when
copying classes.

# Conflicts:
#	compiler/cli/src/org/jetbrains/kotlin/cli/jvm/K2JVMCompiler.kt
#	compiler/frontend.java/src/org/jetbrains/kotlin/config/JVMConfigurationKeys.java

libraries/examples/kotlin-gradle-subplugin-example/src/main/kotlin/example/ExampleSubplugin.kt

@@ -22,7 +22,7 @@ import org.gradle.api.tasks.SourceSet
 import org.gradle.api.tasks.compile.AbstractCompile
 import org.jetbrains.kotlin.gradle.plugin.SubpluginOption
 
-class ExampleSubplugin : KotlinGradleSubplugin {
+class ExampleSubplugin : KotlinGradleSubplugin<AbstractCompile> {
 
     override fun isApplicable(project: Project, task: AbstractCompile): Boolean {
         return true