CI: prevent forks from running jobs for self-hosted

.github/workflows/PR_ARM32-fastbuild.yml

@@ -4,6 +4,7 @@ on: [pull_request]
 
 jobs:
   build-racket3m:
+    if: github.repository == 'racket/racket'
     runs-on: [self-hosted, Linux, ARM]
 
     steps:
@@ -14,6 +15,7 @@ jobs:
       run: make CPUS=$(nproc) PKGS="" bc-in-place
 
   build-racketcs:
+    if: github.repository == 'racket/racket'
     runs-on: [self-hosted, Linux, ARM]
 
     steps:

.github/workflows/PR_ARM64-fastbuild.yml

@@ -4,6 +4,7 @@ on: [pull_request]
 
 jobs:
   build-racket3m:
+    if: github.repository == 'racket/racket'
     container:
       image: racket/racket-ci:latest
                 
@@ -17,6 +18,7 @@ jobs:
       run: make CPUS=$(nproc) PKGS="" bc-in-place
 
   build-racketcs:
+    if: github.repository == 'racket/racket'
     container:
       image: racket/racket-ci:latest
 

.github/workflows/chez-build.yml

@@ -59,6 +59,7 @@ jobs:
         run: ../../../.github/scripts/test.sh
 
   build-arm64:
+    if: github.repository == 'racket/racket'
     runs-on: [self-hosted, ARM64, Linux]
     container:
       image: racket/racket-ci:latest

.github/workflows/ci-push-arm_linux.yml

@@ -9,6 +9,7 @@ jobs:
 # component finishes building.
 
   build-racketcgc:
+    if: github.repository == 'racket/racket'
     runs-on: [self-hosted, Linux, '${{ matrix.arch }}']
     container:
       image: racket/racket-ci:latest
@@ -68,6 +69,7 @@ jobs:
         path: /tmp/racketcgc-debian10-${{ matrix.cify }}-${{ matrix.arch }}_git${{ github.sha }}.tar.bz2
 
   build-racket3m:
+    if: github.repository == 'racket/racket'
     container:
       image: racket/racket-ci:latest
                 
@@ -146,6 +148,7 @@ jobs:
         path: /tmp/racket3m-debian10-${{ matrix.cify }}-${{ matrix.ep }}-${{ matrix.arch }}_git${{ github.sha }}.tar.bz2
 
   build-racketcs:
+    if: github.repository == 'racket/racket'
     container:
       image: racket/racket-ci:latest
 
@@ -202,6 +205,7 @@ jobs:
         path: /tmp/racketcs-debian10-${{ matrix.arch }}_git${{ github.sha }}.tar.bz2
 
   test-3m:
+    if: github.repository == 'racket/racket'
     container:
       image: racket/racket-ci:latest
       options: --init
@@ -277,6 +281,7 @@ jobs:
         run: raco test -c tests/syntax
 
   test-cs:
+    if: github.repository == 'racket/racket'
     container:
       image: racket/racket-ci:latest
       options: --init

.github/workflows/ubsan-arm.yml

@@ -9,6 +9,7 @@ jobs:
 # Build jobs
 # These jobs build Racket using undefined behaviour sanitizers and gathers the results into a final log
   racket3m-ubsan:
+    if: github.repository == 'racket/racket'
     strategy:
       fail-fast: false
       matrix:
@@ -98,6 +99,7 @@ jobs:
         path: runtime-errors-${{ matrix.arch }}_git${{ github.sha }}.log
 
   racketcs-ubsan:
+    if: github.repository == 'racket/racket'
     strategy:
       fail-fast: false
       matrix: