Remove returns unit markers in suspend lambdas

compiler/testData/codegen/bytecodeText/coroutines/returnUnitInLambda.kt

@@ -0,0 +1,29 @@
+// WITH_RUNTIME
+// WITH_COROUTINES
+
+import helpers.*
+import kotlin.coroutines.experimental.*
+import kotlin.coroutines.experimental.intrinsics.*
+// TREAT_AS_ONE_FILE
+
+var res = "FAIL"
+
+suspend fun suspendHere() = suspendCoroutineOrReturn<Unit> {
+    res = "OK"
+    it.resume(Unit)
+    COROUTINE_SUSPENDED
+}
+
+fun builder(c: suspend () -> Unit) {
+    c.startCoroutine(EmptyContinuation)
+}
+
+fun box() : String {
+    builder {
+        suspendHere()
+    }
+    return res
+}
+
+// 0 ICONST_2
+// 0 ICONST_3