CI: use free runners for 5 linux jobs

Author: marcoieni

src/ci/github-actions/jobs.yml

@@ -143,7 +143,7 @@ auto:
     <<: *job-linux-4c
 
   - image: dist-arm-linux
-    <<: *job-linux-8c
+    <<: *job-linux-4c
 
   - image: dist-armhf-linux
     <<: *job-linux-4c
@@ -213,10 +213,10 @@ auto:
     <<: *job-linux-4c
 
   - image: i686-gnu
-    <<: *job-linux-8c
+    <<: *job-linux-4c
 
   - image: i686-gnu-nopt
-    <<: *job-linux-8c
+    <<: *job-linux-4c
 
   - image: mingw-check
     <<: *job-linux-4c
@@ -229,7 +229,7 @@ auto:
     # nightly features to compile, and this job would fail if
     # executed on beta and stable.
     only_on_channel: nightly
-    <<: *job-linux-8c
+    <<: *job-linux-4c
 
   # Tests integration with Rust for Linux.
   # Builds stage 1 compiler and tries to compile a few RfL examples with it.
@@ -263,7 +263,7 @@ auto:
     <<: *job-linux-4c-largedisk
 
   - image: x86_64-gnu-distcheck
-    <<: *job-linux-8c
+    <<: *job-linux-4c
 
   - image: x86_64-gnu-llvm-19
     env: