Add symbolizer to the CI for ASAN

.github/workflows/ci.yml

@@ -286,6 +286,16 @@ jobs:
 
       - uses: camshaft/rust-cache@v1
 
+      # asan expects a binary at /usr/bin/llvm-symbolizer but GHA runners include
+      # multiple versioned binaries, like /usr/bin/llvm-symbolizer-13. This step
+      # finds the latest symbolizer and use it as the "base" llvm-symbolizer binary.
+      #
+      # llvm-symbolizer is necessary to get nice stack traces from asan errors. 
+      # Otherwise the stack trace just contains a hex address like "0x55bc6a28a9b6"
+      - name: set llvm symbolizer
+        run: |
+          sudo ln -s $(find /usr/bin/ -maxdepth 1 -name "llvm-symbolizer-*" | sort -V | tail -n 1) /usr/bin/llvm-symbolizer
+
       - name: Run Unit Tests under ASAN
         env:
           RUSTDOCFLAGS: -Zsanitizer=address