Switch to full ngen for Roslyn binaries

[genlu]

This reverts commit 5536669, the change was originally implemented in #53837

Fixes: https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_workitems/edit/1362616

Val build: https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_build/results?buildId=5036568&view=results
val insertion: https://dev.azure.com/devdiv/DevDiv/_git/VS/pullrequest/341198

[genlu]

The insertion shows reduced jitting across the board and some regression caused by increased image size, which is expected.

[genlu]

FYI @allisonchou @davkean

[allisonchou]

@genlu As someone who's not very familiar with ngen, what implications (if any) will this have on the insertion flow?

[genlu]

@allisonchou based on the RPS results in the val insertion, this would reduce jitting but also might cause regression in refset due to increased image size. The regression should be auto-approved for exception though, since it's expected for full ngen.

FYI, we saw similar refset regression last time we tried to switch to full ngen
https://devdiv.visualstudio.com/DefaultCollection/DevDiv/_git/VS/pullrequest/329020

[davkean]

This regressed this counter which should be looked at:

BuildInfoVS64.Test - RegressedBeyondThreshold / 0001.BuildInfo / Build_Ngen_InvalidAssemblyCount / Regressed: 4.00 Count (21.05%)

[genlu]

@davkean That's unrelated. There's a breaking change in LanguageServer.Client (PR), which requires some additional change in VS repo, which my validation PR doesn't have.