Fix dotnet aarch64 (#9222)

* fix C# aarch64 test after .NET SDK upgrade

* simplify C# aarch64 tests (net60 can build under emulator)

* Revert "simplify C# aarch64 tests (net60 can build under emulator)"

This reverts commit 6b2aa5f006.

kokoro/linux/aarch64/test_csharp_aarch64.sh

@@ -16,7 +16,7 @@ fi
 # Tests are built "dotnet publish" because we want all the dependencies to the copied to the destination directory
 # (we want to avoid references to ~/.nuget that won't be available in the subsequent docker run)
 CSHARP_BUILD_COMMAND="dotnet publish -c Release -f net60 csharp/src/Google.Protobuf.Test/Google.Protobuf.Test.csproj"
-docker run $DOCKER_TTY_ARGS --rm --user "$(id -u):$(id -g)" -e "HOME=/home/fake-user" -e "DOTNET_CLI_TELEMETRY_OPTOUT=true" -e "DOTNET_SKIP_FIRST_TIME_EXPERIENCE=true" -v "$(mktemp -d):/home/fake-user" -v "$(pwd)":/work -w /work mcr.microsoft.com/dotnet/sdk:5.0.202-buster-slim bash -c "$CSHARP_BUILD_COMMAND"
+docker run $DOCKER_TTY_ARGS --rm --user "$(id -u):$(id -g)" -e "HOME=/home/fake-user" -e "DOTNET_CLI_TELEMETRY_OPTOUT=true" -e "DOTNET_SKIP_FIRST_TIME_EXPERIENCE=true" -v "$(mktemp -d):/home/fake-user" -v "$(pwd)":/work -w /work mcr.microsoft.com/dotnet/sdk:6.0.100-bullseye-slim bash -c "$CSHARP_BUILD_COMMAND"
 
 # Use an actual aarch64 docker image to run protobuf C# tests with an emulator. "dotnet vstest" allows
 # running tests from a pre-built project.
@@ -26,4 +26,4 @@ docker run $DOCKER_TTY_ARGS --rm --user "$(id -u):$(id -g)" -e "HOME=/home/fake-
 #   otherwise the UID would be homeless under the docker container and pip install wouldn't work. For simplicity,
 #   we just run map the user's home to a throwaway temporary directory
 CSHARP_TEST_COMMAND="dotnet vstest csharp/src/Google.Protobuf.Test/bin/Release/net60/publish/Google.Protobuf.Test.dll"
-docker run $DOCKER_TTY_ARGS --rm --user "$(id -u):$(id -g)" -e "HOME=/home/fake-user" -e "DOTNET_CLI_TELEMETRY_OPTOUT=true" -e "DOTNET_SKIP_FIRST_TIME_EXPERIENCE=true" -v "$(mktemp -d):/home/fake-user" -v "$(pwd)":/work -w /work mcr.microsoft.com/dotnet/sdk:5.0.202-buster-slim-arm64v8 bash -c "$CSHARP_TEST_COMMAND"
+docker run $DOCKER_TTY_ARGS --rm --user "$(id -u):$(id -g)" -e "HOME=/home/fake-user" -e "DOTNET_CLI_TELEMETRY_OPTOUT=true" -e "DOTNET_SKIP_FIRST_TIME_EXPERIENCE=true" -v "$(mktemp -d):/home/fake-user" -v "$(pwd)":/work -w /work mcr.microsoft.com/dotnet/sdk:6.0.100-bullseye-slim-arm64v8 bash -c "$CSHARP_TEST_COMMAND"