stop timing 8.7.2 (to save some time on the timing runner)

.gitlab-ci.yml

@@ -40,10 +40,6 @@ build-coq.8.7.2:
   <<: *template
   variables:
     OPAM_PINS: "coq version 8.7.2"
-    TIMING_PROJECT: "lambda-rust"
-    TIMING_CONF: "coq-8.7.2"
-  tags:
-  - fp-timing
 
 build-iris.dev:
   <<: *template