switch to the macos-12-xl builder

Author: pietroalbini

.github/workflows/ci.yml

@@ -309,7 +309,7 @@ jobs:
               NO_DEBUG_ASSERTIONS: 1
               NO_OVERFLOW_CHECKS: 1
               DIST_REQUIRE_ALL_TOOLS: 1
-            os: macos-latest
+            os: macos-12-xl
           - name: dist-apple-various
             env:
               SCRIPT: "./x.py dist bootstrap --include-default-paths --host='' --target=aarch64-apple-ios,x86_64-apple-ios,aarch64-apple-ios-sim"
@@ -320,7 +320,7 @@ jobs:
               NO_LLVM_ASSERTIONS: 1
               NO_DEBUG_ASSERTIONS: 1
               NO_OVERFLOW_CHECKS: 1
-            os: macos-latest
+            os: macos-12-xl
           - name: dist-x86_64-apple-alt
             env:
               SCRIPT: "./x.py dist bootstrap --include-default-paths"
@@ -331,7 +331,7 @@ jobs:
               NO_LLVM_ASSERTIONS: 1
               NO_DEBUG_ASSERTIONS: 1
               NO_OVERFLOW_CHECKS: 1
-            os: macos-latest
+            os: macos-12-xl
           - name: x86_64-apple-1
             env:
               SCRIPT: "./x.py --stage 2 test --exclude src/test/ui --exclude src/test/rustdoc --exclude src/test/run-make-fulldeps"
@@ -342,7 +342,7 @@ jobs:
               NO_LLVM_ASSERTIONS: 1
               NO_DEBUG_ASSERTIONS: 1
               NO_OVERFLOW_CHECKS: 1
-            os: macos-latest
+            os: macos-12-xl
           - name: x86_64-apple-2
             env:
               SCRIPT: "./x.py --stage 2 test src/test/ui src/test/rustdoc src/test/run-make-fulldeps"
@@ -353,7 +353,7 @@ jobs:
               NO_LLVM_ASSERTIONS: 1
               NO_DEBUG_ASSERTIONS: 1
               NO_OVERFLOW_CHECKS: 1
-            os: macos-latest
+            os: macos-12-xl
           - name: dist-aarch64-apple
             env:
               SCRIPT: "./x.py dist bootstrap --include-default-paths --stage 2"
@@ -368,7 +368,7 @@ jobs:
               NO_OVERFLOW_CHECKS: 1
               DIST_REQUIRE_ALL_TOOLS: 1
               JEMALLOC_SYS_WITH_LG_PAGE: 14
-            os: macos-latest
+            os: macos-12-xl
           - name: x86_64-msvc-1
             env:
               RUST_CONFIGURE_ARGS: "--build=x86_64-pc-windows-msvc --enable-profiler"

src/ci/github-actions/ci.yml

@@ -77,7 +77,7 @@ x--expand-yaml-anchors--remove:
     <<: *base-job
 
   - &job-macos-xl
-    os: macos-latest  # We don't have an XL builder for this
+    os: macos-12-xl
     <<: *base-job
 
   - &job-windows-xl