Auto merge of rust-lang#112267 - lqd:win-1cgu, r=Kobzol

Build `rustc` with 1CGU on `x86_64-pc-windows-msvc`

Distribute `x86_64-pc-windows-msvc` artifacts built with `rust.codegen-units=1`, like we already do on Linux.

1) effect on code size on `x86_64-pc-windows-msvc`: it's a 3.67% reduction on `rustc_driver.dll`
- before, [`41d97c8a5dea2731b0e56fe97cd7cb79e21cff79`](https://ci-artifacts.rust-lang.org/rustc-builds/41d97c8a5dea2731b0e56fe97cd7cb79e21cff79/rustc-nightly-x86_64-pc-windows-msvc.tar.xz): 137605632
- after, [`704aaa875e4acccc973cbe4579e66afbac425691`](https://ci-artifacts.rust-lang.org/rustc-builds/704aaa875e4acccc973cbe4579e66afbac425691/rustc-nightly-x86_64-pc-windows-msvc.tar.xz): 132551680

2) time it took on CI
- the [first `try` build](https://github.com/rust-lang-ci/rust/actions/runs/8155647651/job/22291592507) took: 1h 31m
- the [second `try` build](https://github.com/rust-lang-ci/rust/actions/runs/8157043594/job/22295790552) took: 1h 32m

3) most recent perf results:
- on a slightly noisy desktop [here](rust-lang#112267 (comment))
- ChrisDenton's results [here](rust-lang#112267 (comment))

Related tracking issue for build configuration: rust-lang#103595

.github/workflows/ci.yml

@@ -442,7 +442,7 @@ jobs:
             os: windows-2019-8core-32gb
           - name: dist-x86_64-msvc
             env:
-              RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-msvc --host=x86_64-pc-windows-msvc --target=x86_64-pc-windows-msvc --enable-full-tools --enable-profiler"
+              RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-msvc --host=x86_64-pc-windows-msvc --target=x86_64-pc-windows-msvc --enable-full-tools --enable-profiler --set rust.codegen-units=1"
               SCRIPT: python x.py build --set rust.debug=true opt-dist && PGO_HOST=x86_64-pc-windows-msvc ./build/x86_64-pc-windows-msvc/stage0-tools-bin/opt-dist windows-ci -- python x.py dist bootstrap --include-default-paths
               DIST_REQUIRE_ALL_TOOLS: 1
             os: windows-2019-8core-32gb

src/ci/github-actions/ci.yml

@@ -692,6 +692,7 @@ jobs:
                 --target=x86_64-pc-windows-msvc
                 --enable-full-tools
                 --enable-profiler
+                --set rust.codegen-units=1
               SCRIPT: python x.py build --set rust.debug=true opt-dist && PGO_HOST=x86_64-pc-windows-msvc ./build/x86_64-pc-windows-msvc/stage0-tools-bin/opt-dist windows-ci -- python x.py dist bootstrap --include-default-paths
               DIST_REQUIRE_ALL_TOOLS: 1
             <<: *job-windows-8c