Rust rlib vendor snapshot support.

Adds support for snapshotting Rust rlibs. This allows us
vendor-specific code that uses rlib-only linkage until dylib
snapshot support is added.

Bug: 184042776
Test: m nothing # new Soong tests pass
Test: Example test Rust vendor module builds
Test: m dist vendor-snapshot # includes rlibs
Change-Id: I4976d3e1efec0ee778cc97730d45be471dffb678
diff --git a/rust/testing.go b/rust/testing.go
index a7cbf54..72f87e1 100644
--- a/rust/testing.go
+++ b/rust/testing.go
@@ -135,6 +135,9 @@
 			apex_available: ["//apex_available:platform", "//apex_available:anyapex"],
 			min_sdk_version: "29",
 			vendor_available: true,
+			llndk: {
+				symbol_file: "liblog.map.txt",
+			},
 		}
 		cc_library {
 			name: "libprotobuf-cpp-full",
@@ -245,4 +248,5 @@
 		ctx.BottomUp("rust_begin", BeginMutator).Parallel()
 	})
 	ctx.RegisterSingletonType("rust_project_generator", rustProjectGeneratorSingleton)
+	registerRustSnapshotModules(ctx)
 }