Add an apex_contributions_defaults module to module sdk

This metadata module will contain a flattened list of all the soong
modules contributed by this module to the rest of the build. This is
supported in V and above.

Bug: 326246905
Test: m art-module-host-exports
Test: unzip -p out/soong/mainline-sdks/art-module-host-exports-current.zip Android.bp | grep -A 15 apex_contributions_defaults
apex_contributions_defaults {
    name: "art-module-host-exports.contributions",
    contents: [
        "prebuilt_art.module.api.annotations",
        "prebuilt_dex2oat",
        "prebuilt_dex2oatd",
        "prebuilt_dexdump",
        "prebuilt_hiddenapi",
        "prebuilt_oatdump",
        "prebuilt_profman",
        "prebuilt_veridex",
        "prebuilt_libartpalette",
        "prebuilt_libartbase",
    ],
}

Change-Id: Iba43a9da5430adfc0a5fd9b5dc27b5d89c5eacb8
diff --git a/sdk/systemserverclasspath_fragment_sdk_test.go b/sdk/systemserverclasspath_fragment_sdk_test.go
index 3c0b8ae..c1c4ed6 100644
--- a/sdk/systemserverclasspath_fragment_sdk_test.go
+++ b/sdk/systemserverclasspath_fragment_sdk_test.go
@@ -34,6 +34,9 @@
 				env["SOONG_SDK_SNAPSHOT_TARGET_BUILD_RELEASE"] = targetBuildRelease
 			}
 		}),
+		android.FixtureModifyProductVariables(func(variables android.FixtureProductVariables) {
+			variables.Platform_version_active_codenames = []string{"VanillaIceCream"}
+		}),
 		prepareForSdkTestWithApex,
 
 		android.FixtureWithRootAndroidBp(sdk+`
@@ -242,6 +245,11 @@
 	expectedLatestSnapshot := `
 // This is auto-generated. DO NOT EDIT.
 
+apex_contributions_defaults {
+    name: "mysdk.contributions",
+    contents: ["prebuilt_mysdklibrary"],
+}
+
 java_sdk_library_import {
     name: "mysdklibrary",
     prefer: false,