[Build] Add smoke test for linux.riscv64

Part of #2310

Author: HannesWell

JenkinsJobs/SmokeTests/StartSmokeTests.jenkinsfile

@@ -35,6 +35,7 @@ spec:
 						name 'MACHINE'
 						values \
 						'opensuse_leap', \
+						'linux_riscv', \
 						'centos9', \
 						'centos8_arm', \
 						'centos8_ppc'
@@ -53,6 +54,9 @@ spec:
 								if (agentId == 'opensuse_leap') {
 									os = 'linux'; arch = 'x86_64'
 									executorAgent = createKubernetesAgent('eclipse/platformreleng-opensuse-gtk3-metacity:15')
+								} else if (agentId == 'linux_riscv') {
+									os = 'linux'; arch = 'riscv64'
+									executorAgent = createLabeledAgent('riscv64')
 								} else if (agentId == 'centos9') {
 									os = 'linux'; arch = 'x86_64'
 									executorAgent = createKubernetesAgent('eclipse/platformreleng-centos-gtk4-mutter:9')