Roll benchmarks-internal to 15a6634bd60ed0b937ed5dbc874cba2da9865514

Change-Id: Ice1ed6cd9f4038d34061e62e177adb8ce6e0c668
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/152643
Reviewed-by: Karl Klose <karlklose@google.com>
Commit-Queue: William Hesse <whesse@google.com>

Author: whesse

DEPS

@@ -48,7 +48,7 @@ vars = {
   "co19_2_rev": "620c1148c8b7a3d7f74afacf348c46f109eb64f2",
 
   # The internal benchmarks to use. See go/dart-benchmarks-internal
-  "benchmarks_internal_rev": "02695da98bcf006b95630d3c386f4169d7ec4ecf",
+  "benchmarks_internal_rev": "15a6634bd60ed0b937ed5dbc874cba2da9865514",
   "checkout_benchmarks_internal": False,
 
   # As Flutter does, we use Fuchsia's GN and Clang toolchain. These revision