Remove KotlinSignature from tests, spec, delete tests with errors

compiler/testData/loadJava/compiledJava/kotlinSignature/CustomProjectionKind.java

@@ -2,10 +2,7 @@ package test;
 
 import java.util.*;
 
-import jet.runtime.typeinfo.KotlinSignature;
-
 public class CustomProjectionKind {
-    @KotlinSignature("fun foo(): MutableList<out Number>")
     public List<Number> foo() {
         throw new UnsupportedOperationException();
     }