LibWasm+Meta: Add test-wasm and optionally test the conformance tests

This only tests "can it be parsed", but the goal of this commit is to
provide a test framework that can be built upon :)
The conformance tests are downloaded, compiled* and installed only if
the INCLUDE_WASM_SPEC_TESTS cmake option is enabled.
(*) Since we do not yet have a wast parser, the compilation is delegated
to an external tool from binaryen, `wasm-as`, which is required for the
test suite download/install to succeed.
This *does* run the tests in CI, but it currently does not include the
spec conformance tests.

Tests/LibWasm/test-wasm.cpp

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2021, Ali Mohammad Pur <mpfard@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibCore/File.h>
+#include <LibTest/JavaScriptTestRunner.h>
+#include <LibWasm/AbstractMachine/Interpreter.h>
+#include <LibWasm/Types.h>
+
+TEST_ROOT("Userland/Libraries/LibWasm/Tests");
+
+TESTJS_GLOBAL_FUNCTION(read_binary_wasm_file, readBinaryWasmFile)
+{
+    auto filename = vm.argument(0).to_string(global_object);
+    if (vm.exception())
+        return {};
+    auto file = Core::File::open(filename, Core::OpenMode::ReadOnly);
+    if (file.is_error()) {
+        vm.throw_exception<JS::TypeError>(global_object, file.error());
+        return {};
+    }
+    auto contents = file.value()->read_all();
+    auto array = JS::Uint8Array::create(global_object, contents.size());
+    contents.span().copy_to(array->data());
+    return array;
+}
+
+TESTJS_GLOBAL_FUNCTION(parse_webassembly_module, parseWebAssemblyModule)
+{
+    auto object = vm.argument(0).to_object(global_object);
+    if (vm.exception())
+        return {};
+    if (!is<JS::Uint8Array>(object)) {
+        vm.throw_exception<JS::TypeError>(global_object, "Expected a Uint8Array argument to parse_webassembly_module");
+        return {};
+    }
+    auto& array = static_cast<JS::Uint8Array&>(*object);
+    InputMemoryStream stream { array.data() };
+    auto result = Wasm::Module::parse(stream);
+    if (result.is_error()) {
+        vm.throw_exception<JS::SyntaxError>(global_object, Wasm::parse_error_to_string(result.error()));
+        return {};
+    }
+    if (stream.handle_any_error())
+        return JS::js_undefined();
+    return JS::js_null();
+}
+
+TESTJS_GLOBAL_FUNCTION(compare_typed_arrays, compareTypedArrays)
+{
+    auto lhs = vm.argument(0).to_object(global_object);
+    if (vm.exception())
+        return {};
+    if (!is<JS::TypedArrayBase>(lhs)) {
+        vm.throw_exception<JS::TypeError>(global_object, "Expected a TypedArray");
+        return {};
+    }
+    auto& lhs_array = static_cast<JS::TypedArrayBase&>(*lhs);
+    auto rhs = vm.argument(1).to_object(global_object);
+    if (vm.exception())
+        return {};
+    if (!is<JS::TypedArrayBase>(rhs)) {
+        vm.throw_exception<JS::TypeError>(global_object, "Expected a TypedArray");
+        return {};
+    }
+    auto& rhs_array = static_cast<JS::TypedArrayBase&>(*rhs);
+    return JS::Value(lhs_array.viewed_array_buffer()->buffer() == rhs_array.viewed_array_buffer()->buffer());
+}