Add "art-systemserverclasspath-fragment" to ART SDK.

After this change, a prebuilt "art-systemserverclasspath-fragment" will
be generated when a new SDK is built.

Bug: 194150908
Test: m out/soong/.intermediates/art/build/sdk/art-module-sdk/common_os/snapshot/Android.bp
Change-Id: Ice39ad509702fe2c129f9e6782cc2b054ffe389d
1 file changed