add back release mode

Author: amykhuang

.github/workflows/libc-fullbuild-tests.yml

@@ -15,7 +15,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        # Build basic linux configuration with Debug and MinSizeRel and all
+        # Build basic linux configuration with Debug/Release/MinSizeRel and all
         # other configurations in Debug only.
         include:
           - os: ubuntu-24.04
@@ -25,6 +25,13 @@ jobs:
             cpp_compiler: clang++-21
             target: x86_64-unknown-linux-llvm
             include_scudo: ON
+          - os: ubuntu-24.04
+            build_type: Release
+            ccache-variant: sccache
+            c_compiler: clang-21
+            cpp_compiler: clang++-21
+            target: x86_64-unknown-linux-llvm
+            include_scudo: ON
           - os: ubuntu-24.04
             build_type: MinSizeRel
             ccache-variant: sccache