tests: add kotlin examples

Author: vil02

tests/unused_example_data/kotlin/function_used_twice.kt

@@ -0,0 +1,14 @@
+fun fun0() {
+    print('{')
+    print('%')
+}
+
+fun fun1() {
+    fun0()
+    println()
+    fun0()
+}
+
+fun main() {
+    fun1()
+}

tests/unused_example_data/kotlin/one_empty_function.kt

@@ -0,0 +1,10 @@
+fun fun0() {}
+
+fun fun1() {
+    fun0()
+    print('C')
+}
+
+fun main() {
+    fun1()
+}

tests/unused_example_data/kotlin/single_atom.kt

@@ -0,0 +1,3 @@
+fun main() {
+    print('X')
+}

tests/unused_example_data/kotlin/trivial.kt

@@ -0,0 +1 @@
+fun main() {}