DefaultServlet should not overwrite programmatically configured precompressed formats with defaults

[markslater]

Jetty version(s)
11.0.9
Java version/vendor (use: java -version)
N/A
OS type/version
N/A
Description
When DefaultServlet is instantiated, most of the properties of its ResourceService retain their values unless they have been configured by an InitParameter. This means the behaviour can be configured programmatically on the ResourceService. However, this does not hold for the PrecompressedFormats, which are always reset to defaults if no InitParameter is set.

How to reproduce?
Given the following code, the PrecompressedFormats will be ignored:

ResourceService resourceService = new ResourceService();
resourceService.setPrecompressedFormats(new CompressedContentFormat[]{
        new CompressedContentFormat("bzip2", ".bz2"),
        new CompressedContentFormat("gzip", ".gz"),
        new CompressedContentFormat("br", ".br")
});
ServletHolder defholder = new ServletHolder(new DefaultServlet(resourceService));
context.addServlet(defholder, "/");