[JS IR] Don't use JVM-specific mangler in JS IR backend

^KT-54638 Fixed

compiler/ir/serialization.js/build.gradle.kts

@@ -5,6 +5,7 @@ plugins {
 
 dependencies {
     api(project(":compiler:ir.psi2ir"))
+    api(project(":compiler:fir:fir2ir"))
     api(project(":compiler:ir.serialization.common"))
     api(project(":js:js.frontend"))
 

compiler/ir/serialization.js/src/org/jetbrains/kotlin/fir/backend/js/FirJsKotlinMangler.kt

@@ -0,0 +1,31 @@
+/*
+ * Copyright 2010-2023 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 org.jetbrains.kotlin.fir.backend.js
+
+import org.jetbrains.kotlin.backend.common.serialization.mangle.KotlinExportChecker
+import org.jetbrains.kotlin.backend.common.serialization.mangle.KotlinMangleComputer
+import org.jetbrains.kotlin.backend.common.serialization.mangle.MangleMode
+import org.jetbrains.kotlin.fir.NoMutableState
+import org.jetbrains.kotlin.fir.backend.FirBasedKotlinMangler
+import org.jetbrains.kotlin.fir.backend.FirExportCheckerVisitor
+import org.jetbrains.kotlin.fir.backend.FirMangleComputer
+import org.jetbrains.kotlin.fir.declarations.FirDeclaration
+
+@NoMutableState
+class FirJsKotlinMangler : FirBasedKotlinMangler() {
+
+    private class JsFirExportChecker : FirExportCheckerVisitor() {
+        override fun FirDeclaration.isPlatformSpecificExported() = false
+    }
+
+    override fun getExportChecker(compatibleMode: Boolean): KotlinExportChecker<FirDeclaration> {
+        return JsFirExportChecker()
+    }
+
+    override fun getMangleComputer(mode: MangleMode, compatibleMode: Boolean): KotlinMangleComputer<FirDeclaration> {
+        return FirMangleComputer(StringBuilder(256), mode)
+    }
+}