Profile and performance test Diagnostics middleware

During the #42384 I noticed that the Diagnostics middleware, mainly `StatusCodePages` middleware, allocated much more than expected

| application | statuscodepages | nostatuscodepages+content | |
| --------------------------------------- | --------------- | ------------------------- | ---------- |
| Max Working Set (MB) | 179 | 186 | +3.74% |
| Max GC Heap Size (MB) | 90 | 94 | +4.21% |
| Size of committed memory by the GC (MB) | 117 | 119 | +1.28% |
| Max Number of Gen 0 GCs / sec | 41.00 | 25.00 | -39.02% |
| Max Number of Gen 1 GCs / sec | 1.00 | 13.00 | +1,200.00% |
| Max Number of Gen 2 GCs / sec | 0.00 | 1.00 | +∞% |
| Max Time in GC (%) | 2.00 | 1.00 | -50.00% |
| Max Gen 0 Size (B) | 3,152,512 | 5,146,600 | +63.25% |
| Max Gen 1 Size (B) | 9,309,256 | 5,376,536 | -42.25% |
| Max Gen 2 Size (B) | 1,970,808 | 6,406,424 | +225.07% |
| Max LOH Size (B) | 411,320 | 411,320 | 0.00% |
| Max POH Size (B) | 3,472,456 | 3,451,856 | -0.59% |
| Total Allocated Bytes | 96,805,446,920 | 57,737,869,840 | -40.36% |
| Max GC Heap Fragmentation | 30 | 41 | +36.47% |

| load | statuscodepages | nostatuscodepages+content | |
| ---------------------- | --------------- | ------------------------- | ------- |
| Requests/sec | 1,354,620 | 1,429,729 | +5.54% |
| Requests | 20,454,730 | 21,588,730 | +5.54% |

**nostatuscodepages+content** => `endpoints.MapGet("sample", () => Results.Content(new string(' ', 500), statusCode: 415));`

`new string(' ', 500)` is similar to what the `StatusCodePages` does.

Since this middleware, and other Diagnostics middleware, will become more relevant after the introducing of `ProblemDetails` Services, we should do some profiling and optimizing of these middleware, including scenarios that produce a `ProblemDetails` payload.

Locate the Diagnostics middleware, especially StatusCodePages, and reproduce the issue with the sample endpoint using new string(' ', 500). Profile requests with and without StatusCodePages, including scenarios that produce a ProblemDetails payload; done means allocation and performance findings are validated and the relevant middleware is optimized.

Written by the indexing model from the issue text.