Refacor install_pipeline_crd SYSTEM_NAMESPACE env setup

This commit refactors the setup for `SYSTEM_NAMESPACE` which was
previously set in the `install_pipeline_crd` helper function. But it
should not be necessary to be part of the pipeline installation instead
it is an env setup. This helps resolve the issue where we could not
run tests before installing the current version of pipeline CRDs.

test/e2e-common.sh

@@ -31,8 +31,6 @@ function install_pipeline_crd() {
   verify_pipeline_installation
   verify_resolvers_installation
   verify_log_access_enabled
-
-  export SYSTEM_NAMESPACE=tekton-pipelines
 }
 
 # Install the Tekton pipeline crd based on the release number

test/e2e-tests-upgrade.sh

@@ -45,6 +45,8 @@ set -o nounset
 
 export SYSTEM_NAMESPACE=tekton-pipelines
 
+export SYSTEM_NAMESPACE=tekton-pipelines
+
 # First, we will verify if Scenario 1 works.
 # Install the previous release.
 header "Install the previous release of Tekton pipeline $PREVIOUS_PIPELINE_VERSION"

test/e2e-tests.sh

@@ -43,6 +43,7 @@ fi
 header "Setting up environment"
 
 install_pipeline_crd
+export SYSTEM_NAMESPACE=tekton-pipelines
 
 failed=0