Fix parameter comments that don't match the formal parameter name

More information:
https://docs.google.com/a/google.com/document/d/1lzK04DqCZgjOoGQfBT053QIrCvlsyAAwLo0jfqcN6ds/edit?usp=sharing

Tested:
    TAP --sample ran all affected tests and none failed
    http://test/OCL:324422822:BASE:324408434:1596318556672:a8b3beed
PiperOrigin-RevId: 324621068

library/core/src/test/java/com/google/android/exoplayer2/analytics/DefaultPlaybackSessionManagerTest.java

@@ -171,7 +171,7 @@ public final class DefaultPlaybackSessionManagerTest {
                 /* isDynamic= */ false,
                 /* durationUs= */ 10_000_000,
                 FakeTimeline.createAdPlaybackState(
-                    /* adsPerGroup= */ 1, /* adGroupTimesUs... */ 0)));
+                    /* adsPerAdGroup= */ 1, /* adGroupTimesUs... */ 0)));
     MediaPeriodId adMediaPeriodId =
         new MediaPeriodId(
             timeline.getUidOfPeriod(/* periodIndex= */ 0),
@@ -557,7 +557,7 @@ public final class DefaultPlaybackSessionManagerTest {
                 /* isDynamic= */ false,
                 /* durationUs= */ 10_000_000,
                 FakeTimeline.createAdPlaybackState(
-                    /* adsPerGroup= */ 1, /* adGroupTimesUs... */ 0)));
+                    /* adsPerAdGroup= */ 1, /* adGroupTimesUs... */ 0)));
     MediaPeriodId contentMediaPeriodId =
         new MediaPeriodId(
             timeline.getUidOfPeriod(/* periodIndex= */ 0), /* windowSequenceNumber= */ 0);