prefer precompiled rustc for x86_64-gnu

Signed-off-by: onur-ozkan <work@onurozkan.dev>

Author: onur-ozkan

.github/workflows/ci.yml

@@ -58,9 +58,10 @@ jobs:
           - name: mingw-check-tidy
             os: ubuntu-20.04-4core-16gb
             env: {}
-          - name: x86_64-gnu-llvm-16
+          - name: x86_64-gnu
             env:
               ENABLE_GCC_CODEGEN: "1"
+              DOWNLOAD_RUSTC: "1"
             os: ubuntu-20.04-16core-64gb
           - name: x86_64-gnu-tools
             os: ubuntu-20.04-16core-64gb
@@ -295,7 +296,8 @@ jobs:
             env: {}
           - name: x86_64-gnu
             os: ubuntu-20.04-4core-16gb
-            env: {}
+            env:
+              DOWNLOAD_RUSTC: "1"
           - name: x86_64-gnu-stable
             env:
               IMAGE: x86_64-gnu

src/ci/github-actions/ci.yml

@@ -357,9 +357,10 @@ jobs:
           - name: mingw-check-tidy
             <<: *job-linux-4c
 
-          - name: x86_64-gnu-llvm-16
+          - name: x86_64-gnu
             env:
               ENABLE_GCC_CODEGEN: "1"
+              DOWNLOAD_RUSTC: "1"
             <<: *job-linux-16c
 
           - name: x86_64-gnu-tools
@@ -476,6 +477,8 @@ jobs:
             <<: *job-linux-8c
 
           - name: x86_64-gnu
+            env:
+              DOWNLOAD_RUSTC: "1"
             <<: *job-linux-4c
 
           # This job ensures commits landing on nightly still pass the full