Use tail call optimization if ARETURN has multiple sources

#KT-21977: Fixed

compiler/testData/codegen/bytecodeListing/tailCallIntrinsics.kt

@@ -0,0 +1,18 @@
+// WITH_RUNTIME
+import kotlin.coroutines.experimental.*
+import kotlin.coroutines.experimental.intrinsics.*
+
+var p: Int = 5846814
+private suspend fun withoutInline() {
+    val c = { c: Continuation<Unit> ->
+        if (p > 52158) Unit else COROUTINE_SUSPENDED
+    }
+
+    return suspendCoroutineOrReturn(c)
+}
+
+private suspend fun withInline() {
+    return suspendCoroutineOrReturn { c ->
+        if (p > 52158) Unit else COROUTINE_SUSPENDED
+    }
+}

compiler/testData/codegen/bytecodeListing/tailCallIntrinsics.txt

@@ -0,0 +1,20 @@
+@kotlin.Metadata
+final class TailCallIntrinsicsKt$withoutInline$c$1 {
+    public final static field INSTANCE: TailCallIntrinsicsKt$withoutInline$c$1
+    inner class TailCallIntrinsicsKt$withoutInline$c$1
+    static method <clinit>(): void
+    method <init>(): void
+    public final @org.jetbrains.annotations.NotNull method invoke(@org.jetbrains.annotations.NotNull p0: kotlin.coroutines.experimental.Continuation): java.lang.Object
+    public synthetic method invoke(p0: java.lang.Object): java.lang.Object
+}
+
+@kotlin.Metadata
+public final class TailCallIntrinsicsKt {
+    private static field p: int
+    inner class TailCallIntrinsicsKt$withoutInline$c$1
+    static method <clinit>(): void
+    public final static method getP(): int
+    public final static method setP(p0: int): void
+    final static @org.jetbrains.annotations.Nullable method withInline(@org.jetbrains.annotations.NotNull p0: kotlin.coroutines.experimental.Continuation): java.lang.Object
+    final static @org.jetbrains.annotations.Nullable method withoutInline(@org.jetbrains.annotations.NotNull p0: kotlin.coroutines.experimental.Continuation): java.lang.Object
+}