JVM multithreaded scope pool now turned on by default

lynglib/src/wasmJsMain/kotlin/net/sergeych/lyng/ScopePoolWasm.kt

@@ -0,0 +1,27 @@
+package net.sergeych.lyng
+
+import net.sergeych.lyng.obj.Obj
+import net.sergeych.lyng.obj.ObjVoid
+
+/**
+ * Wasm/JS actual: simple global deque pool (single-threaded runtime model).
+ */
+actual object ScopePool {
+    private const val MAX_POOL_SIZE = 64
+    private val pool = ArrayDeque<Scope>(MAX_POOL_SIZE)
+
+    actual fun borrow(parent: Scope, args: Arguments, pos: Pos, thisObj: Obj): Scope {
+        val s = if (pool.isNotEmpty()) pool.removeLast() else Scope(parent, args, pos, thisObj)
+        if (s.parent !== parent || s.args !== args || s.pos !== pos || s.thisObj !== thisObj) {
+            s.resetForReuse(parent, args, pos, thisObj)
+        } else {
+            s.frameId = nextFrameId()
+        }
+        return s
+    }
+
+    actual fun release(scope: Scope) {
+        scope.resetForReuse(parent = null, args = Arguments.EMPTY, pos = Pos.builtIn, thisObj = ObjVoid)
+        if (pool.size < MAX_POOL_SIZE) pool.addLast(scope)
+    }
+}