Remove e2e/framework/profile_gatherer.go

Since 59533f0 which removes the
deprecated scalability tests, functions in profile_gatherer.go have
not been used at all.
So this removes e2e/framework/profile_gatherer.go

Author: Kenichi Omichi

test/e2e/framework/BUILD

@@ -15,7 +15,6 @@ go_library(
         "log_size_monitoring.go",
         "nodes_util.go",
         "pods.go",
-        "profile_gatherer.go",
         "provider.go",
         "psp.go",
         "rc_util.go",