Use cooperative coroutine cancellation in test code

Our test code relies on `withTimeout*` and `while(true)`
in a few places to wait for things to happen. However,
having a timeout is not enough: if the coroutine is busy,
even if the timeout elapses, the work will not be interrupted.
That's because cancellation in Kotlin coroutines is cooperative,
see [the docs](https://github.com/Kotlin/kotlinx.coroutines/blob/master/docs/cancellation-and-timeouts.md#cancellation-is-cooperative)
for more details.

This commit uses cooperative cancellation so that tests will
break, instead of hanging forever.

glean-core/android/src/main/java/mozilla/telemetry/glean/utils/WorkManagerUtils.kt

@@ -8,6 +8,7 @@ import android.content.Context
 import androidx.work.WorkInfo
 import androidx.work.WorkManager
 import androidx.work.testing.WorkManagerTestInitHelper
+import kotlinx.coroutines.isActive
 import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.withTimeout
 
@@ -35,7 +36,7 @@ internal fun testFlushWorkManagerJob(context: Context, workTag: String, timeoutM
                         return@withTimeout
                     }
                 }
-            } while (true)
+            } while (isActive)
         }
     }
 }

glean-core/android/src/test/java/mozilla/telemetry/glean/DispatchersTest.kt

@@ -9,6 +9,7 @@ import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.Dispatchers as KotlinDispatchers
 import kotlinx.coroutines.Job
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.isActive
 import kotlinx.coroutines.joinAll
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.runBlocking
@@ -107,7 +108,7 @@ class DispatchersTest {
         // Wait for the flushed tasks to be executed.
         runBlocking {
             withTimeoutOrNull(2000) {
-                while (threadCanary.get() != 3 || Dispatchers.API.taskQueue.size > 0) {
+                while (isActive && (threadCanary.get() != 3 || Dispatchers.API.taskQueue.size > 0)) {
                     delay(1)
                 }
             } ?: assertTrue("Timed out waiting for tasks to execute", false)
@@ -157,7 +158,7 @@ class DispatchersTest {
         runBlocking {
             // Ensure that all the required jobs have been added to the list.
             withTimeoutOrNull(2000) {
-                while (counter.get() < 100) {
+                while (isActive && counter.get() < 100) {
                     delay(1)
                 }
             } ?: assertEquals("Timed out waiting for tasks to execute", 100, counter.get())

glean-core/android/src/test/java/mozilla/telemetry/glean/TestUtil.kt

@@ -13,6 +13,7 @@ import androidx.test.core.app.ApplicationProvider
 import androidx.work.WorkInfo
 import androidx.work.WorkManager
 import androidx.work.testing.WorkManagerTestInitHelper
+import kotlinx.coroutines.isActive
 import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.withTimeout
 import org.json.JSONObject
@@ -197,7 +198,7 @@ internal fun waitForEnqueuedWorker(
             if (getWorkerStatus(context, workTag).isEnqueued) {
                 return@withTimeout
             }
-        } while (true)
+        } while (isActive)
     }
 }