Assert that version checking won't throw on startup (#1512)

# Overview

Previously if the coproc came up later, getProperty would return the
string literal "null", which made us print the BFW. Add tests to make
sure that we don't do that anymore by rebooting a sim coproc +
robot in a combination of different orders.

photon-lib/src/test/java/org/photonvision/UnitTestUtils.java

@@ -0,0 +1,74 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) PhotonVision
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package org.photonvision;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
+
+import java.util.function.BooleanSupplier;
+import org.photonvision.targeting.PhotonPipelineResult;
+
+public class UnitTestUtils {
+    static void waitForCondition(String name, BooleanSupplier condition) {
+        // wait up to 1 second for satisfaction
+        for (int i = 0; i < 100; i++) {
+            if (condition.getAsBoolean()) {
+                System.out.println(name + " satisfied on iteration " + i);
+                return;
+            }
+
+            try {
+                Thread.sleep(60);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+                fail(e);
+            }
+        }
+        throw new RuntimeException(name + " was never satisfied");
+    }
+
+    static PhotonPipelineResult waitForSequenceNumber(PhotonCamera camera, int seq) {
+        assertTrue(camera.heartbeatEntry.getTopic().getHandle() != 0);
+
+        System.out.println(
+                "Waiting for seq=" + seq + " on " + camera.heartbeatEntry.getTopic().getName());
+        // wait up to 1 second for a new result
+        for (int i = 0; i < 100; i++) {
+            var res = camera.getLatestResult();
+            System.out.println(res);
+            if (res.metadata.sequenceID == seq) {
+                return res;
+            }
+
+            try {
+                Thread.sleep(60);
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+                fail(e);
+            }
+        }
+        throw new RuntimeException("Never saw sequence number " + seq);
+    }
+}