Bootstrap/Load: Ensure WP_Fatal_Error_Handler does not conflict with existing mechanisms treating fatal errors.

Prior to this change, resuming or activating a plugin or theme that is still broken would result in a redirect loop if in recovery mode. If outside recovery mode, it would cause the error template to be displayed.

Furthermore this applies to breaking a plugin or theme when editing from the backend.

Props aandrewdixon, azaozz, dhanukanuwan, henrywright, ocean90, ohiosierra, PandelisZ, xkon.
Fixes #46045, #46751.


git-svn-id: https://develop.svn.wordpress.org/trunk@45114 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/load.php

@@ -1444,6 +1444,7 @@ function wp_start_scraping_edited_file_errors() {
 		echo "###### wp_scraping_result_end:$key ######";
 		die();
 	}
+	define( 'WP_SANDBOX_SCRAPING', true );
 	register_shutdown_function( 'wp_finalize_scraping_edited_file_errors', $key );
 }