Revert^2 "Convert per-test run scripts to python."

This reverts commit 8d6a4e021e1dc4717939e05aee89c9b18e383d12.

Reason for revert: Reland

Test: test.py -r --all-target
Test: diff emitted test commands before and after
Change-Id: I8b99d9b3804615f2ebc50171a4368ad87d809300
diff --git a/test/055-enum-performance/run b/test/055-enum-performance/run
index e27a622..dbb09fd 100755
--- a/test/055-enum-performance/run
+++ b/test/055-enum-performance/run
@@ -14,5 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# As this is a performance test we always use the non-debug build.
-exec ${RUN} "${@/#libartd.so/libart.so}"
+
+def run(ctx, args):
+  # As this is a performance test we always use the non-debug build.
+  ctx.default_run(args, lib="libart.so")