Try LTO for Windows

Author: Kobzol

src/ci/github-actions/jobs.yml

@@ -83,7 +83,7 @@ envs:
     # - not running `opt-dist`'s post-optimization smoke tests on the resulting toolchain
     #
     # If you *want* these to happen however, temporarily uncomment it before triggering a try build.
-    DIST_TRY_BUILD: 1
+#    DIST_TRY_BUILD: 1
 
   auto:
     <<: *production
@@ -554,6 +554,7 @@ auto:
         --enable-full-tools
         --enable-profiler
         --set rust.codegen-units=1
+        --set rust.lto=thin
       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
       CODEGEN_BACKENDS: llvm,cranelift