Improve wp_is_stream() performance

[swissspidy]

The wp_is_stream() function (used by functions like wp_normalize_path() currently uses a dynamically constructed regex to detect streams. This could be verified a lot by using in_array() instead.

@schlessera suggested the following version over at ​https://github.com/wp-cli/wp-cli/issues/5008:

function wp_is_stream( $path ) {
    $scheme_separator = strpos( $path, '://' );

    if ( false === $scheme_separator ) {
        // $path isn't a stream
        return false;
    }
 
    $stream = substr( $path, 0, $scheme_separator );

    return in_array( $stream, stream_get_wrappers(), true );
}

​A quick benchmark shows that this is around four times faster than the current method.

[pento]

In 44506:

Filesystem: Improve wp_is_stream() performance.

Instead of turning the return value of stream_get_wrappers() into a regex to match the scheme, we can instead extract the scheme and search the return value of stream_get_wrappers().

Props schlessera, swissspidy.
Fixes #45553.