Ignore unreachable code on tail call optimization

#KT-21759: Fixed

compiler/testData/codegen/box/coroutines/tailCallOptimizations/unreachable.kt

@@ -0,0 +1,24 @@
+// WITH_RUNTIME
+// WITH_COROUTINES
+import helpers.*
+import kotlin.coroutines.experimental.*
+import kotlin.coroutines.experimental.intrinsics.*
+
+suspend fun twoReturns(c: suspend () -> Unit) {
+    return c()
+    throw RuntimeException("FAIL 1")
+}
+
+fun builder(c: suspend () -> Unit) {
+    c.startCoroutine(EmptyContinuation)
+}
+
+fun box(): String {
+    var res = "FAIL"
+    builder {
+        twoReturns {
+            res = "OK"
+        }
+    }
+    return res
+}