LibJS: Do not use the $ special character in file names

The dollar sign is a special character in POSIX shells and in the Ninja
build file format. If the file name contains a `$`, something goes wrong
in the escaping/unescaping of this symbol, and CMake/GCC/Clang generate
invalid dependency files where not all instances of `$` are escaped
properly. Because of this, Ninja fails to rebuild `$262Object.cpp` if
the headers included by it have changed.

Stale `$262Object.cpp.o` files have been the cause of mysterious crashes
multiple times which only go away after doing a clean build. Let's
prevent these from happening again by removing the `$` from the
filename.

Userland/Libraries/LibJS/Contrib/Test262/262Object.cpp

@@ -5,9 +5,11 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+// NOTE: This file is not named $262Object.cpp because dollar signs in file names cause issues with some build tools.
+
 #include <AK/TypeCasts.h>
 #include <LibJS/Bytecode/Interpreter.h>
-#include <LibJS/Contrib/Test262/$262Object.h>
+#include <LibJS/Contrib/Test262/262Object.h>
 #include <LibJS/Contrib/Test262/AgentObject.h>
 #include <LibJS/Contrib/Test262/GlobalObject.h>
 #include <LibJS/Contrib/Test262/IsHTMLDDA.h>

Userland/Libraries/LibJS/Contrib/Test262/GlobalObject.cpp

@@ -5,7 +5,7 @@
  */
 
 #include <AK/Format.h>
-#include <LibJS/Contrib/Test262/$262Object.h>
+#include <LibJS/Contrib/Test262/262Object.h>
 #include <LibJS/Contrib/Test262/AgentObject.h>
 #include <LibJS/Contrib/Test262/GlobalObject.h>
 #include <LibJS/Heap/Cell.h>

Userland/Libraries/LibJS/Contrib/Test262/GlobalObject.h

@@ -6,7 +6,7 @@
 
 #pragma once
 
-#include <LibJS/Contrib/Test262/$262Object.h>
+#include <LibJS/Contrib/Test262/262Object.h>
 #include <LibJS/Runtime/GlobalObject.h>
 
 namespace JS::Test262 {