LibJS: Reorganize tests into subfolders

Author: https://github.com/mattco98
Commit: 4c48c9d69d
Pull-request: https://github.com/SerenityOS/serenity/pull/2681
Reviewed-by: https://github.com/linusg

Libraries/LibJS/Tests/builtins/Number/Number.isNaN.js

@@ -0,0 +1,31 @@
+load("test-common.js");
+
+try {
+    assert(Number.isNaN !== isNaN);
+    assert(Number.isNaN.length === 1);
+
+    assert(Number.isNaN(0) === false);
+    assert(Number.isNaN(42) === false);
+    assert(Number.isNaN("") === false);
+    assert(Number.isNaN("0") === false);
+    assert(Number.isNaN("42") === false);
+    assert(Number.isNaN(true) === false);
+    assert(Number.isNaN(false) === false);
+    assert(Number.isNaN(null) === false);
+    assert(Number.isNaN([]) === false);
+    assert(Number.isNaN(Infinity) === false);
+    assert(Number.isNaN(-Infinity) === false);
+    assert(Number.isNaN() === false);
+    assert(Number.isNaN(undefined) === false);
+    assert(Number.isNaN("foo") === false);
+    assert(Number.isNaN({}) === false);
+    assert(Number.isNaN([1, 2, 3]) === false);
+
+    assert(Number.isNaN(NaN) === true);
+    assert(Number.isNaN(Number.NaN) === true);
+    assert(Number.isNaN(0 / 0) === true);
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e.message);
+}