Add CI check to test patch file (#253)

This tests that the patch file can apply in CI.

.circleci/config.pkl

@@ -21,7 +21,9 @@ import "jobs/GradleCheckJob.pkl"
 import "jobs/DeployJob.pkl"
 import "jobs/SimpleGradleJob.pkl"
 
-local prbJobs: Listing<String> = gradleCheckJobs.keys.toListing()
+local prbJobs: Listing<String> = (gradleCheckJobs.keys.toListing()) {
+  "check-patch-file"
+}
 
 local buildAndTestJobs = (prbJobs) {
   "bench"
@@ -151,4 +153,18 @@ jobs {
       }
     }
   }
+  ["check-patch-file"] {
+    docker {
+      new { image = "cimg/base:current" }
+    }
+    steps {
+      "checkout"
+      new RunStep {
+        // language=bash
+        command = #"""
+        git apply --reject patches/graalVm23.patch
+        """#
+      }
+    }
+  }
 }