Revert max-width styles on caption shortcodes.

This is a partial revert of [41724], so image captions include an
inline `width` style instead of `max-width`.

This returns the caption shortcode to the pre-4.9.0 behavior, while
retaining the extra unit test coverage added in [41724].

Fixes #43123. See #33981.

Built from https://develop.svn.wordpress.org/trunk@42837


git-svn-id: http://core.svn.wordpress.org/trunk@42667 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/media.php

@@ -1603,7 +1603,7 @@ function img_caption_shortcode( $attr, $content = null ) {
 
 	$style = '';
 	if ( $caption_width ) {
-		$style = 'style="max-width: ' . (int) $caption_width . 'px" ';
+		$style = 'style="width: ' . (int) $caption_width . 'px" ';
 	}
 
 	if ( $html5 ) {

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.0-alpha-42836';
+$wp_version = '5.0-alpha-42837';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.