Change the packaging of leveldb tests and benchmarks.

For tests, move them off the deprecated_system_package and move the
executable from bin/ to tests/ (that should enable them on CI/CQ).

For benchmarks, create a separate package that provides a single binary,
so that they could be manually run on the Fuchsia device.

Change-Id: I54446588ae55c5f0dfa3a5513b0f95739139cb49
diff --git a/BUILD.gn b/BUILD.gn
index 83e4d73..51a8565 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -6,13 +6,12 @@
 
 package("leveldb_tests") {
   testonly = true
-  deprecated_system_image = true
 
   deps = [
     ":leveldb_tests_bin",
   ]
 
-  binaries = [
+  tests = [
     {
       name = "leveldb_tests"
     },
@@ -278,8 +277,23 @@
   configs += [ ":leveldb_warnings_config" ]
 }
 
+package("leveldb_benchmarks") {
+  testonly = true
+
+  deps = [
+    ":leveldb_db_bench",
+  ]
+
+  binaries = [
+    {
+      name = "leveldb_db_benchmark"
+    },
+  ]
+}
+
 executable("leveldb_db_bench") {
   testonly = true
+  output_name = "leveldb_db_benchmark"
 
   sources = [
     "db/db_bench.cc",