Stop exporting systemserverclasspath_fragment when targeting S

Previously, when targeting the S release the generated sdk snapshot
would contain prebuilt_systemserverclasspath_fragment modules even
though they were only added in T.

This allows SdkMemberTypes to specify the set of target build releases
they support and ignores them when targeting an unsupported target
build release.

Test: m nothing
      packages/modules/common/build/mainline_modules_sdks.sh
      # Check that the for-S-build snapshots do not include SSCPFs.
Bug: 237718221
Change-Id: I2df08c2fcebf9b866695d691572a9d3783758b17

sdk/systemserverclasspath_fragment_sdk_test.go

@@ -22,13 +22,16 @@ import (
 	"android/soong/java"
 )
 
-func TestSnapshotWithSystemServerClasspathFragment(t *testing.T) {
+func testSnapshotWithSystemServerClasspathFragment(t *testing.T, targetBuildRelease string, expectedSdkSnapshot string) {
 	result := android.GroupFixturePreparers(
 		prepareForSdkTestWithJava,
 		java.PrepareForTestWithJavaDefaultModules,
 		java.PrepareForTestWithJavaSdkLibraryFiles,
 		java.FixtureWithLastReleaseApis("mysdklibrary"),
 		dexpreopt.FixtureSetApexSystemServerJars("myapex:mylib", "myapex:mysdklibrary"),
+		android.FixtureModifyEnv(func(env map[string]string) {
+			env["SOONG_SDK_SNAPSHOT_TARGET_BUILD_RELEASE"] = targetBuildRelease
+		}),
 		prepareForSdkTestWithApex,
 
 		android.FixtureWithRootAndroidBp(`
@@ -83,7 +86,34 @@ func TestSnapshotWithSystemServerClasspathFragment(t *testing.T) {
 	).RunTest(t)
 
 	CheckSnapshot(t, result, "mysdk", "",
-		checkAndroidBpContents(`
+		checkAndroidBpContents(expectedSdkSnapshot),
+	)
+}
+
+func TestSnapshotWithSystemServerClasspathFragment(t *testing.T) {
+	t.Run("target-s", func(t *testing.T) {
+		testSnapshotWithSystemServerClasspathFragment(t, "S", `
+// This is auto-generated. DO NOT EDIT.
+
+java_sdk_library_import {
+    name: "mysdklibrary",
+    prefer: false,
+    visibility: ["//visibility:public"],
+    apex_available: ["myapex"],
+    shared_library: false,
+    public: {
+        jars: ["sdk_library/public/mysdklibrary-stubs.jar"],
+        stub_srcs: ["sdk_library/public/mysdklibrary_stub_sources"],
+        current_api: "sdk_library/public/mysdklibrary.txt",
+        removed_api: "sdk_library/public/mysdklibrary-removed.txt",
+        sdk_version: "current",
+    },
+}
+`)
+	})
+
+	t.Run("target-t", func(t *testing.T) {
+		testSnapshotWithSystemServerClasspathFragment(t, "Tiramisu", `
 // This is auto-generated. DO NOT EDIT.
 
 java_sdk_library_import {
@@ -120,6 +150,6 @@ prebuilt_systemserverclasspath_fragment {
         "mysdklibrary",
     ],
 }
-`),
-	)
+`)
+	})
 }