Update DEPS for benchmarks internal

The new benchmarks-internal revision has dart2 benchmarks deleted.

Change-Id: I758d3aaf2bd4c80fb2833be6f1b854e4748e742f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/449927
Commit-Queue: Stephen Adams <[email protected]>
Reviewed-by: Mayank Patke <[email protected]>

Author: rakudrama

DEPS

@@ -57,7 +57,7 @@ vars = {
   "co19_rev": "0cc2ca355dc7ddf041b771f247a01a4ea0d16fd8",
 
   # The internal benchmarks to use. See go/dart-benchmarks-internal
-  "benchmarks_internal_rev": "1fa5d33a45f7d4dd0093124706cdfa45d9270851",
+  "benchmarks_internal_rev": "13eb8dedf372e4255e64349b6e57960f7de4df2d",
   "checkout_benchmarks_internal": False,
 
   # Checkout the flute benchmark only when benchmarking.