Do not remove the race response map entry in Lookup Race Response (#1807)

Author: sisidovski

index.bs

@@ -4157,7 +4157,6 @@ spec: storage; urlPrefix: https://storage.spec.whatwg.org/
       1. Let |map| be |activeWorker|'s [=service worker/global object=]'s [=race response map=].
       1. If |map|[|request|] [=map/exists=], then:
         1. Let |entry| be |map|[|request|].
-        1. [=map/Remove=] |map|[|request|].
         1. Wait until |entry|'s [=race response/value=] is not "<code>pending</code>"
         1. If |entry|'s [=race response/value=] is [=/response=], return |entry|'s [=race response/value=].
       1. Return null.