Only restart full request when restarting requests with thumbnails.

When thumbnail requests finish after full requests complete, we discard
the thumbnail's resource to decrease memory usage and we set the
thumbnails status to complete. When requests are restarted after they
complete, we just call onLoadComplete with whatever resource they had
previously. As a result, thumbnail requests that completed after full
requests were calling onLoadComplete(null), causing spammy error logs
and potentially undesireable calls to onLoadFailed.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=177489960

library/src/main/java/com/bumptech/glide/request/ThumbnailRequestCoordinator.java

@@ -110,7 +110,9 @@ private boolean parentIsAnyResourceSet() {
   @Override
   public void begin() {
     isRunning = true;
-    if (!thumb.isRunning()) {
+    // If the request has completed previously, there's no need to restart both the full and the
+    // thumb, we can just restart the full.
+    if (!full.isComplete() && !thumb.isRunning()) {
       thumb.begin();
     }
     if (isRunning && !full.isRunning()) {

library/src/test/java/com/bumptech/glide/request/ThumbnailRequestCoordinatorTest.java

@@ -85,6 +85,33 @@ public void testDoesNotStartThumbOnRunIfRunning() {
     verify(thumb, never()).begin();
   }
 
+  @Test
+  public void begin_whenFullIsComplete_startsFull() {
+    when(full.isComplete()).thenReturn(true);
+
+    coordinator.begin();
+
+    verify(full).begin();
+  }
+
+  @Test
+  public void begin_whenFullIsComplete_doesNotBeginThumb() {
+    when(full.isComplete()).thenReturn(true);
+
+    coordinator.begin();
+
+    verify(thumb, never()).begin();
+  }
+
+  @Test
+  public void begin_whenFullIsComplete_doesNotSetRunning() {
+    when(full.isComplete()).thenReturn(true);
+
+    coordinator.begin();
+
+    assertThat(coordinator.isRunning()).isFalse();
+  }
+
   @Test
   public void testDoesNotStartFullIfClearedByThumb() {
     doAnswer(new Answer<Void>() {