stdlib: add function to null out spilled dead variables in suspend

functions.

Calls to it are generated by compiler and its implementation is
replaced by debugger

 #KT-63720

Author: ilmirus

libraries/stdlib/jvm/src/kotlin/coroutines/jvm/internal/Spilling.kt

@@ -0,0 +1,17 @@
+/*
+ * Copyright 2010-2024 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin.coroutines.jvm.internal
+
+/**
+ * This function is called by generated code when visible dead variable is spilled.
+ *
+ * By default, it returns `null`, but the debugger is expected to replace it with implementation, which returns the argument.
+ *
+ * This way, we avoid memory leaks, and do not hinder debuggability.
+ */
+@PublishedApi
+@Suppress("UNUSED_PARAMETER", "unused")
+internal fun nullOutSpilledVariable(value: Any?): Any? = null

libraries/tools/binary-compatibility-validator/reference-public-api/kotlin-stdlib-runtime-merged.txt

@@ -3112,6 +3112,10 @@ public abstract interface class kotlin/coroutines/jvm/internal/CoroutineStackFra
 	public abstract fun getStackTraceElement ()Ljava/lang/StackTraceElement;
 }
 
+public final class kotlin/coroutines/jvm/internal/SpillingKt {
+	public static final fun nullOutSpilledVariable (Ljava/lang/Object;)Ljava/lang/Object;
+}
+
 public abstract interface class kotlin/enums/EnumEntries : java/util/List, kotlin/jvm/internal/markers/KMappedMarker {
 }