feat: Introduce Native Image testing build script changes (#1240)

Adds additional switch case to build.sh to accommodate native image testing.
Source-Link: googleapis/synthtool@d45942b
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-java:latest@sha256:d4b2141d65566523dfd523f63c6e6899ab1281463bce182a9f600e74b0511875

.github/.OwlBot.lock.yaml

@@ -1,3 +1,3 @@
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-java:latest
-  digest: sha256:13b7387edb404234610d30473ac48210ae7fe42a136335ee2b2f8a07c4c7f6a5
+  digest: sha256:d4b2141d65566523dfd523f63c6e6899ab1281463bce182a9f600e74b0511875

.kokoro/presubmit/graalvm-native.cfg

@@ -0,0 +1,33 @@
+# Format: //devtools/kokoro/config/proto/build.proto
+
+# Configure the docker image for kokoro-trampoline.
+env_vars: {
+  key: "TRAMPOLINE_IMAGE"
+  value: "gcr.io/cloud-devrel-kokoro-resources/graalvm"
+}
+
+env_vars: {
+  key: "JOB_TYPE"
+  value: "graalvm"
+}
+
+# TODO: remove this after we've migrated all tests and scripts
+env_vars: {
+  key: "GCLOUD_PROJECT"
+  value: "gcloud-devel"
+}
+
+env_vars: {
+  key: "GOOGLE_CLOUD_PROJECT"
+  value: "gcloud-devel"
+}
+
+env_vars: {
+  key: "GOOGLE_APPLICATION_CREDENTIALS"
+  value: "secret_manager/java-it-service-account"
+}
+
+env_vars: {
+  key: "SECRET_MANAGER_KEYS"
+  value: "java-it-service-account"
+}