Use explicit names of our large runners

PiperOrigin-RevId: 650360525

.github/workflows/test_cpp.yml

@@ -19,9 +19,9 @@ jobs:
         config:
           - { name: Optimized, flags: --config=opt }
           - { name: Debug, flags: --config=dbg }
-          - { name: ASAN, flags: --config=asan, runner: ubuntu-20-large }
-          - { name: MSAN, flags: --config=docker-msan, runner: ubuntu-20-large }
-          - { name: TSAN, flags: --config=tsan, runner: ubuntu-20-large }
+          - { name: ASAN, flags: --config=asan, runner: ubuntu-20-4core }
+          - { name: MSAN, flags: --config=docker-msan, runner: ubuntu-20-4core }
+          - { name: TSAN, flags: --config=tsan, runner: ubuntu-20-4core }
           - { name: UBSAN, flags: --config=ubsan }
           - { name: No-RTTI, flags: --cxxopt=-fno-rtti }
         include:
@@ -77,7 +77,7 @@ jobs:
       matrix:
         arch: [x86_64, aarch64]
     name: Linux Release ${{ matrix.arch}}
-    runs-on: ubuntu-20-large
+    runs-on: ubuntu-20-4core
     steps:
       - name: Checkout pending changes
         uses: protocolbuffers/protobuf-ci/checkout@v2

.github/workflows/test_upb.yml

@@ -19,7 +19,7 @@ jobs:
         config:
           - { name: "Fastbuild" }
           - { name: "Optimized", flags: "-c opt" }
-          - { name: "ASAN", flags: "--config=asan -c dbg", exclude-targets: "-//benchmarks:benchmark -//python/...", runner: ubuntu-20-large }
+          - { name: "ASAN", flags: "--config=asan -c dbg", exclude-targets: "-//benchmarks:benchmark -//python/...", runner: ubuntu-20-4core }
           - { name: "UBSAN", flags: "--config=ubsan -c dbg", exclude-targets: "-//benchmarks:benchmark -//python/... -//lua/..." }
           - { name: "32-bit", flags: "--copt=-m32 --linkopt=-m32", exclude-targets: "-//benchmarks:benchmark -//python/..." }
           # TODO: b/297027295 - Add 32-bit ASAN test