[3.11] gh-103726: Set up gcc-10 for ASAN (gh-103728) (#104794)

Set up gcc-10 for ASAN CI as the existing config's default 9.x does not
play well with `vfork()`.

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* Issue: gh-103726
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(cherry picked from commit 8330580800)

Co-authored-by: Dong-hee Na <donghee.na@python.org>

.github/workflows/build.yml

@@ -338,6 +338,10 @@ jobs:
       run: echo "::add-matcher::.github/problem-matchers/gcc.json"
     - name: Install Dependencies
       run: sudo ./.github/workflows/posix-deps-apt.sh
+    - name: Set up GCC-10 for ASAN
+      uses: egor-tensin/setup-gcc@v1
+      with:
+        version: 10
     - name: Configure OpenSSL env vars
       run: |
         echo "MULTISSL_DIR=${GITHUB_WORKSPACE}/multissl" >> $GITHUB_ENV