test: run JSRuntime test func directly

Instead of calling the bultin test functions
Indeed, it causes issue with type comparison.
See https://github.com/lightpanda-io/browsercore/pull/184#issuecomment-1964369066

src/run_tests.zig

@@ -36,7 +36,6 @@ fn testExecFn(
     js_env: *jsruntime.Env,
     comptime execFn: jsruntime.ContextExecFn,
 ) anyerror!void {
-
     // start JS env
     try js_env.start(alloc);
     defer js_env.stop();
@@ -89,6 +88,8 @@ fn testsAllExecFn(
 }
 
 pub fn main() !void {
+    try testJSRuntime();
+
     std.debug.print("\n", .{});
     for (builtin.test_functions) |test_fn| {
         try test_fn.func();
@@ -104,7 +105,7 @@ test {
     std.testing.refAllDecls(DumpTest);
 }
 
-test "jsruntime" {
+fn testJSRuntime() !void {
     // generate tests
     try generate.tests();