Change clone command to make it easier to pin test-infra version. (#28941)

tools/internal_ci/linux/grpc_e2e_performance_gke.sh

@@ -65,11 +65,12 @@ TEST_INFRA_GOVERSION=go1.17.1
 go get "golang.org/dl/${TEST_INFRA_GOVERSION}"
 "${TEST_INFRA_GOVERSION}" download
 
-# Fetch test-infra repository and build all tools.
+# Clone test-infra repository and build all tools.
 pushd ..
-git clone --depth 1 https://github.com/grpc/test-infra.git
+git clone https://github.com/grpc/test-infra.git
 cd test-infra
-git log -1 --oneline
+# Tools are built from HEAD.
+git checkout --detach
 make GOCMD="${TEST_INFRA_GOVERSION}" all-tools
 popd
 

tools/internal_ci/linux/grpc_e2e_performance_gke_experiment.sh

@@ -63,11 +63,12 @@ TEST_INFRA_GOVERSION=go1.17.1
 go get "golang.org/dl/${TEST_INFRA_GOVERSION}"
 "${TEST_INFRA_GOVERSION}" download
 
-# Note: Submodules are not required for tools build.
+# Clone test-infra repository and build all tools.
 pushd ..
-git clone --depth 1 https://github.com/grpc/test-infra.git
+git clone https://github.com/grpc/test-infra.git
 cd test-infra
-git log -1 --oneline
+# Tools are built from HEAD.
+git checkout --detach
 make GOCMD="${TEST_INFRA_GOVERSION}" all-tools
 popd