backend/tests: Add blackbox tests from Kotlin JVM

Added tests from testData/codegen/box directory. There are blackbox tests
in other directories and they are to be added.

backend.native/tests/external/codegen/blackbox/elvis/kt6694ExactAnnotationForElvis.kt

@@ -0,0 +1,19 @@
+interface PsiElement {
+    fun <T: PsiElement> findChildByType(i: Int): T? =
+            if (i == 42) JetOperationReferenceExpression() as T else throw Exception()
+}
+interface JetSimpleNameExpression : PsiElement {
+    fun getReferencedNameElement(): PsiElement
+}
+class JetOperationReferenceExpression : JetSimpleNameExpression {
+    override fun getReferencedNameElement() = this
+}
+class JetLabelReferenceExpression : JetSimpleNameExpression {
+    public override fun getReferencedNameElement(): PsiElement =
+            findChildByType(42) ?: this
+}
+
+fun box(): String {
+    val element = JetLabelReferenceExpression().getReferencedNameElement()
+    return if (element is JetOperationReferenceExpression) "OK" else "fail"
+}