Revert "initial perf, which gets stripped out in production (#4131)" (#4636)

This reverts commit 5ea2150ae7.

src/core/plugins/spec/actions.js

@@ -104,10 +104,6 @@ export const resolveSpec = (json, url) => ({specActions, specSelectors, errActio
 
   let specStr = specSelectors.specStr()
 
-  /* develblock:start */
-  require("root/src/perf").start("resolve")
-  /* develblock:end */
-
   return resolve({
     fetch,
     spec: json,
@@ -135,9 +131,6 @@ export const resolveSpec = (json, url) => ({specActions, specSelectors, errActio
         errActions.newThrownErrBatch(preparedErrors)
       }
 
-    /* develblock:start */
-    require("root/src/perf").stop("resolve")
-    /* develblock:end */
       return specActions.updateResolved(spec)
     })
 }