Bug 1689966 [wpt PR 27420] - Remove non-Array support for idl_test ar…

…guments srcs and deps, a=testonly

Automatic update from web-platform-tests
Remove non-Array support for idl_test arguments srcs and deps (#27420)

--

wpt-commits: f54724aafa338462324ded6c12283478684da223
wpt-pr: 27420

testing/web-platform/tests/resources/idlharness.js

@@ -3543,8 +3543,6 @@ IdlNamespace.prototype.test = function ()
 function idl_test(srcs, deps, idl_setup_func) {
     return promise_test(function (t) {
         var idl_array = new IdlArray();
-        srcs = (srcs instanceof Array) ? srcs : [srcs] || [];
-        deps = (deps instanceof Array) ? deps : [deps] || [];
         var setup_error = null;
         const validationIgnored = [
             "constructor-member",