KAPT: Skip importing java.lang.System in the stubs

This fixes KT-43117

plugins/kapt3/kapt3-compiler/testData/converter/strangeIdentifiers.txt

@@ -1,5 +1,3 @@
-import java.lang.System;
-
 @java.lang.annotation.Retention(value = java.lang.annotation.RetentionPolicy.RUNTIME)
 @kotlin.Metadata()
 public abstract @interface Anno {
@@ -12,8 +10,6 @@ public abstract @interface Anno {
 ////////////////////
 
 
-import java.lang.System;
-
 @kotlin.Metadata()
 public enum StrangeEnum {
     /*public static final*/ InvalidFieldName /* = new StrangeEnum() */;
@@ -32,8 +28,6 @@ public enum StrangeEnum {
 ////////////////////
 
 
-import java.lang.System;
-
 @kotlin.Metadata()
 public final class Test {
     public java.lang.String simpleName;