CI: revert the mmap_rnd_bits kludge

This reverts commit 2e0c2fb8fb and commit
b7c7498de8 now that
https://github.com/actions/runner-images/issues/9491 is closed.

.github/workflows/build_test.yml

@@ -34,8 +34,5 @@ jobs:
     steps:
       - name: Repository checkout
         uses: actions/checkout@9bb56186c3b09b4f86b1c65136769dd318469633
-      # FIXME: drop once https://github.com/actions/runner-images/issues/9491  is resolved
-      - name: Reduce ASLR entropy
-        run: sudo sysctl -w vm.mmap_rnd_bits=28
       - name: Build check
         run: .github/workflows/build_test.sh

.github/workflows/cflite_pr.yml

@@ -23,7 +23,6 @@ jobs:
       matrix:
         sanitizer: [address, undefined, memory]
     steps:
-    - run: sudo sysctl -w vm.mmap_rnd_bits=28
     - name: Build Fuzzers
       id: build
       uses: google/clusterfuzzlite/actions/build_fuzzers@v1

.github/workflows/cifuzz.yml

@@ -39,7 +39,6 @@ jobs:
       security-events: write
 
     steps:
-      - run: sudo sysctl -w vm.mmap_rnd_bits=28
       - name: Build Fuzzers
         id: build
         uses: google/oss-fuzz/infra/cifuzz/actions/build_fuzzers@master

.github/workflows/unit_tests.yml

@@ -31,9 +31,6 @@ jobs:
     steps:
       - name: Repository checkout
         uses: actions/checkout@9bb56186c3b09b4f86b1c65136769dd318469633
-      # FIXME: drop once https://github.com/actions/runner-images/issues/9491  is resolved
-      - name: Reduce ASLR entropy
-        run: sudo sysctl -w vm.mmap_rnd_bits=28
       - name: Install build dependencies
         run: |
           # Drop XDG_* stuff from /etc/environment, so we don't get the user