RFR: 8248131: Simplify ServicesCatalog provider handling

[Mandy Chung]

On 6/23/20 1:56 AM, Claes Redestad wrote:
> Hi,
>
> the current implementation of ServicesCatalog uses an internal providers
> method, which is only used to add ServiceProviders.
>
> Providing an addProviders method instead means we can streamline this,
> to the tune of a very small startup win.
>
> Bug:    https://bugs.openjdk.java.net/browse/JDK-8248131
> Webrev: http://cr.openjdk.java.net/~redestad/8248131/open.00/
>
Looks okay to me.

Mandy