Address flakiness of i.q..jacoco.runtime.DataFileWatchTest

The `DataFileWatchTest` appears to be [flaky](https://ge.quarkus.io/scans/tests?search.relativeStartTime=P90D&search.timeZoneId=Europe%2FLondon&tests.container=io.quarkus.jacoco.runtime.DataFileWatchTest&tests.test=waitForDataFileThatNeverAppears).

The failed assertion (`Future.isDone()`) in the `waitForDataFileThatNeverAppears()` test case asserts that the data-file watch function is still running. Is is technically not guaranteed, as the test executor thread may not get scheduled until the `DataFileWatch.waitForDataFile()` function finished.

This change updates the assertion in the mentioned test case to `assertThat(future).succeedsWithin(FUTURE_WAIT_DURATION).isEqualTo...`, which is good enough.

Additional, related changes:
* Remove the racy/flaky assertion on `Future.isDone()`
* Increase the future-wait-duration to a very long time to account for stalled test executions in GH CI workflows (many things running concurrently/in-parallel).
* Unify all test cases to use the same approach

Fixes the flaky test reported in #30315 by @Sanne

Author: snazy

test-framework/jacoco/runtime/src/test/java/io/quarkus/jacoco/runtime/DataFileWatchTest.java

@@ -6,6 +6,7 @@
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.time.Duration;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
@@ -22,6 +23,9 @@
 
 public class DataFileWatchTest {
 
+    // This is a rather long timeout due to the GH runner instances running many things concurrently.
+    static final Duration FUTURE_WAIT_DURATION = Duration.ofMinutes(15);
+
     @TempDir
     Path tempDir;
 
@@ -55,7 +59,7 @@ public void dataFileSize() throws Exception {
     }
 
     @Test
-    public void waitForDataFileGoodCase() throws Exception {
+    public void waitForDataFileGoodCase() {
         // Scenario:
         // - The Jacoco data file does not already exist
         // - File created after 2 wait iterations
@@ -92,7 +96,7 @@ void waitSleep() {
 
         Future<Boolean> future = executor.submit(dataFileWatch::waitForDataFile);
 
-        assertThat(future.get(30, TimeUnit.SECONDS)).isTrue();
+        assertThat(future).succeedsWithin(FUTURE_WAIT_DURATION).isEqualTo(true);
         assertThat(waitIterations.get()).isEqualTo(2);
         assertThat(error.get()).isNull();
     }
@@ -136,13 +140,13 @@ void waitSleep() {
 
         Future<Boolean> future = executor.submit(dataFileWatch::waitForDataFile);
 
-        assertThat(future.get(30, TimeUnit.SECONDS)).isTrue();
+        assertThat(future).succeedsWithin(FUTURE_WAIT_DURATION).isEqualTo(true);
         assertThat(waitIterations.get()).isEqualTo(2);
         assertThat(error.get()).isNull();
     }
 
     @Test
-    public void waitForDataFileJacocoStillRunning() throws Exception {
+    public void waitForDataFileJacocoStillRunning() {
         // Scenario:
         // - The Jacoco data file does not already exist
         // - file created after 2 wait iterations
@@ -174,15 +178,15 @@ void waitSleep() {
 
         Future<Boolean> future = executor.submit(dataFileWatch::waitForDataFile);
 
-        assertThat(future.get(30, TimeUnit.SECONDS)).isFalse();
+        assertThat(future).succeedsWithin(FUTURE_WAIT_DURATION).isEqualTo(false);
         assertThat(waitIterations.get()).isEqualTo(0);
         assertThat(error.get()).isEqualTo(String.format(
                 "Timed out waiting for Jacoco data file %s update, file size before test run: did not exist, current file size: 100",
                 datafile));
     }
 
     @Test
-    public void waitForDataFileThatNeverAppears() throws Exception {
+    public void waitForDataFileThatNeverAppears() {
         // Scenario:
         // - The Jacoco data file does not already exist,
         // - The data file never appears
@@ -205,8 +209,8 @@ void waitSleep() {
 
         Future<Boolean> future = executor.submit(dataFileWatch::waitForDataFile);
 
-        assertThat(future.isDone()).isFalse();
-        assertThat(future.get(30, TimeUnit.SECONDS)).isFalse();
+        assertThat(future).succeedsWithin(FUTURE_WAIT_DURATION).isEqualTo(false);
+        assertThat(waitIterations.get()).isEqualTo(0);
         assertThat(error.get()).isEqualTo(String.format(
                 "Timed out waiting for Jacoco data file %s update, file size before test run: did not exist, current file size: does not exist",
                 datafile));
@@ -238,8 +242,8 @@ void waitSleep() {
 
         Future<Boolean> future = executor.submit(dataFileWatch::waitForDataFile);
 
-        assertThat(future.isDone()).isFalse();
-        assertThat(future.get(30, TimeUnit.SECONDS)).isFalse();
+        assertThat(future).succeedsWithin(FUTURE_WAIT_DURATION).isEqualTo(false);
+        assertThat(waitIterations.get()).isEqualTo(0);
         assertThat(error.get()).isEqualTo(String.format(
                 "Timed out waiting for Jacoco data file %s update, file size before test run: 100, current file size: 100",
                 datafile));