Remove speed program link from README.md.

This doc was never added; if we want to add it in the future we can put
the link back at that time.

Change-Id: I2c23121f7844e6bae5d653259ef9578d70e98674
Reviewed-on: https://chromium-review.googlesource.com/572181
Reviewed-by: Ben Henry <benhenry@chromium.org>
Commit-Queue: Annie Sullivan <sullivan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#486876}

docs/speed/README.md

@@ -17,7 +17,6 @@
   * [I want Chrome to have better performance](help_improve_performance.md)
   * [Perf sheriffing documentation](perf_regression_sheriffing.md)
   * [I want to add tests or platforms to the perf waterfall](adding_tests_bots.md)
-  * [I'm looking for more information on the Speed Progam](speed_program.md)
 
 ## Core Teams and Work