Fixed test crashing due to nullability problems

Author: volivan239

utbot-framework/src/main/kotlin/org/utbot/framework/codegen/model/visitor/CgKotlinRenderer.kt

@@ -202,7 +202,8 @@ internal class CgKotlinRenderer(context: CgRendererContext, printer: CgPrinter =
     }
 
     override fun renderAccess(caller: CgExpression) {
-        print("?.")
+        if (caller.type.isNullable) print("?")
+        print(".")
     }
 
     override fun visit(element: CgParameterDeclaration) {

utbot-framework/src/main/kotlin/org/utbot/framework/codegen/model/visitor/UtilMethods.kt

@@ -343,7 +343,7 @@ private fun createInstance(visibility: Visibility, language: CodegenLanguage): S
         }
         CodegenLanguage.KOTLIN -> {
             """
-            ${visibility by language}fun createInstance(className: String): kotlin.Any? {
+            ${visibility by language}fun createInstance(className: String): kotlin.Any {
                 val clazz: Class<*> = Class.forName(className)
                 return Class.forName("sun.misc.Unsafe").getDeclaredMethod("allocateInstance", Class::class.java)
                     .invoke(getUnsafeInstance(), clazz)