perf(gatsby): drop severe scaling regression caused by analytics (#24709

)

* perf(gatsby): drop severe scaling regression caused by analytics

Regression introduced in #22851

The problem seems to be that these calls to `v8.serialize` trigger the gc to start a full hold-the-world mark-and-sweep step sooner. In a benchmark of 150k files, the step would trigger almost always after between 100k and 110k queries had run, and it would pause the process for 60+ seconds.

Example benchmark results from before and after that PR:

```
info bootstrap finished - 86.758 s
success Building production JavaScript and CSS bundles - 9.404s
success run queries - 205.676s - 150002/150002 729.31/s
success Building static HTML for pages - 142.800s - 150002/150002 1050.44/s
info Done building in 451.33 sec
```

```
info bootstrap finished - 85.933 s
success Building production JavaScript and CSS bundles - 8.335s
success run queries - 84.795s - 150002/150002 1769.00/s
success Building static HTML for pages - 141.000s - 150002/150002 1063.84/s
info Done building in 320.158 sec
```

This is very consistent behavior. We looked at the change and agreed that the best was to just drop this measurement since it was for the sake of analytics and a non-vital metric to record. We'd rather have the perf than the metric.

Numbers for the fix, same benchmark, first on current master and then on this PR:

```
info bootstrap finished - 79.788s
success Building production JavaScript and CSS bundles - 9.635s
success run queries - 201.542s - 150002/150002 744.27/s
success Building static HTML for pages - 141.535s - 150002/150002 1059.82/s
info Done building in 440.766 sec
```

```
info bootstrap finished - 80.751s
success Building production JavaScript and CSS bundles - 9.570s
success run queries - 87.162s - 150002/150002 1720.95/s
success Building static HTML for pages - 142.609s - 150002/150002 1051.84/s
info Done building in 319.151 sec
```

nice!

* And drop the import

packages/gatsby/src/query/graphql-runner.ts

@@ -1,5 +1,4 @@
 import crypto from "crypto"
-import v8 from "v8"
 import { Span } from "opentracing"
 import {
   parse,
@@ -156,13 +155,6 @@ export class GraphQLRunner {
       if (typeof statsQuery !== `string`) {
         statsQuery = statsQuery.body
       }
-      this.stats.uniqueOperations.add(
-        crypto
-          .createHash(`sha1`)
-          .update(statsQuery)
-          .update(v8.serialize(context))
-          .digest(`hex`)
-      )
 
       this.stats.uniqueQueries.add(
         crypto.createHash(`sha1`).update(statsQuery).digest(`hex`)