JVM_IR: Lazyly generate continuation classes of suspend functions

Otherwise, they will be generated, but unused, if the function is tail-call.
 #KT-36795 Fixed

compiler/testData/codegen/bytecodeText/coroutines/debug/thisAndResultInLvt.kt

@@ -30,9 +30,8 @@ class A {
 // JVM_IR_TEMPLATES
 // <init>, invoke, invokeSuspend, create
 // 4 LOCALVARIABLE this LThisAndResultInLvtKt\$c\$1; L0 L.* 0
-// TODO: Continuation are generated even for tail-call suspend functions: KT-36795
-// c's lambda and foo's and dummy's continuation
-// 3 LOCALVARIABLE \$result Ljava/lang/Object; L0 L.* 1
+// c's lambda and foo's continuation
+// 2 LOCALVARIABLE \$result Ljava/lang/Object; L0 L.* 1
 
 // foo and <init>
 // 2 LOCALVARIABLE this LA; L0 L.* 0