[JS IR BE] Use Char boxing rules of current backend

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/AutoboxingTransformer.kt

@@ -13,9 +13,7 @@ import org.jetbrains.kotlin.ir.backend.js.ir.JsIrBuilder
 import org.jetbrains.kotlin.ir.backend.js.utils.realOverrideTarget
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.expressions.*
-import org.jetbrains.kotlin.ir.types.IrType
-import org.jetbrains.kotlin.ir.types.isNothing
-import org.jetbrains.kotlin.ir.types.makeNotNull
+import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.ir.util.*
 
 
@@ -73,6 +71,13 @@ class AutoboxingTransformer(val context: JsIrBackendContext) : AbstractValueUsag
         val actualInlinedClass = actualType.getInlinedClass()
         val expectedInlinedClass = expectedType.getInlinedClass()
 
+        // Mimicking behaviour of current JS backend
+        // TODO: Revisit
+        if (
+            (actualType is IrDynamicType && expectedType.makeNotNull().isChar()) ||
+            (actualType.makeNotNull().isChar() && expectedType is IrDynamicType)
+        ) return this
+
         val function = when {
             actualInlinedClass == null && expectedInlinedClass == null -> return this
             actualInlinedClass != null && expectedInlinedClass == null -> context.intrinsics.jsBoxIntrinsic