JVM: streamline handling of tail-call suspend functions

Just see if every suspend call is followed only by safe instructions or
returns, then insert a suspension point check if there isn't a direct
return.

The first part of this is equivalent to the old implementation, just
refactored. The second part generates strictly more checks; see, for
example, the fixed test, in which the previous implementation failed to
insert a check before a CHECKCAST.

^KT-51818 Fixed

compiler/testData/codegen/box/coroutines/tailCallOptimizations/checkcast2.kt

@@ -0,0 +1,29 @@
+// TARGET_BACKEND: JVM
+// FULL_JDK
+// WITH_STDLIB
+// WITH_COROUTINES
+// CHECK_TAIL_CALL_OPTIMIZATION
+import helpers.*
+import kotlin.coroutines.*
+import kotlin.coroutines.intrinsics.*
+
+suspend fun suspendFun(x: String): String = suspendCoroutineUninterceptedOrReturn {
+    TailCallOptimizationChecker.saveStackTrace(it)
+    COROUTINE_SUSPENDED
+}
+
+suspend fun myFunWithTailCall(x: String) {
+    x.let { suspendFun(it) }
+}
+
+fun builder(c: suspend () -> Unit) {
+    c.startCoroutine(EmptyContinuation)
+}
+
+fun box(): String {
+    builder {
+        myFunWithTailCall("...")
+    }
+    TailCallOptimizationChecker.checkNoStateMachineIn("myFunWithTailCall")
+    return "OK"
+}