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/controlStructures/doWhileWithContinue.kt

@@ -0,0 +1,21 @@
+fun box(): String {
+    var i = 0
+    do {
+        if (i++ > 100) break;
+        continue;
+    } while(false)
+    if (i != 1) return "Fail 1, expected 1, but $i"
+
+    i = 0
+    do {
+        if (i++ > 100) break;
+        continue;
+    } while(i<10)
+    if (i != 10) return "Fail 2, expected 10, but $i"
+
+    i = 0
+    do continue while(i++<10)
+    if (i != 11) return "Fail 3, expected 11, but $i"
+
+    return "OK"
+}