[Wasm] Use Wasm GC arrays instead of JS arrays

JS arrays was a workaround for lack of arrays in Firefox Wasm GC prototype
Now with V8 as a test runner we can use proper arrays

wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/Declarations.kt

@@ -145,6 +145,11 @@ class WasmStructDeclaration(
     val fields: List<WasmStructFieldDeclaration>
 ) : WasmTypeDeclaration(name)
 
+class WasmArrayDeclaration(
+    name: String,
+    val field: WasmStructFieldDeclaration
+) : WasmTypeDeclaration(name)
+
 class WasmStructFieldDeclaration(
     val name: String,
     val type: WasmType,

wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/convertors/WasmIrToBinary.kt

@@ -26,7 +26,7 @@ class WasmIrToBinary(outputStream: OutputStream, val module: WasmModule) {
                 gcTypes.forEach {
                     when (it) {
                         is WasmStructDeclaration -> appendStructTypeDeclaration(it)
-                        else -> TODO("Support arrays")
+                        is WasmArrayDeclaration -> appendArrayTypeDeclaration(it)
                     }
                 }
             }
@@ -197,15 +197,24 @@ class WasmIrToBinary(outputStream: OutputStream, val module: WasmModule) {
         }
     }
 
+    private fun appendFiledType(field: WasmStructFieldDeclaration) {
+        appendType(field.type)
+        b.writeVarUInt1(field.isMutable)
+    }
+
     private fun appendStructTypeDeclaration(type: WasmStructDeclaration) {
         b.writeVarInt7(-0x21)
         b.writeVarUInt32(type.fields.size)
         type.fields.forEach {
-            appendType(it.type)
-            b.writeVarUInt1(it.isMutable)
+            appendFiledType(it)
         }
     }
 
+    private fun appendArrayTypeDeclaration(type: WasmArrayDeclaration) {
+        b.writeVarInt7(-0x22)
+        appendFiledType(type.field)
+    }
+
     val WasmFunctionType.index: Int
         get() = module.functionTypes.indexOf(this)
 

wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/convertors/WasmIrToText.kt

@@ -201,8 +201,9 @@ class WasmIrToText : SExpressionBuilder() {
                     when (it) {
                         is WasmStructDeclaration ->
                             appendStructTypeDeclaration(it)
-                        else ->
-                            TODO("Support arrays")
+                        is WasmArrayDeclaration ->
+                            appendArrayTypeDeclaration(it)
+                        else -> error("Unexpected GC type: $it")
                     }
                 }
                 importsInOrder.forEach {
@@ -253,6 +254,16 @@ class WasmIrToText : SExpressionBuilder() {
         }
     }
 
+    private fun appendArrayTypeDeclaration(type: WasmArrayDeclaration) {
+        newLineList("type") {
+            appendModuleFieldReference(type)
+            sameLineList("array") {
+                appendStructField(type.field)
+            }
+        }
+    }
+
+
     private fun appendImportedFunction(function: WasmFunction.Imported) {
         newLineList("func") {
             appendModuleFieldReference(function)