Add @SuppressWarnings("ComparableType") for instances of a class implementing 'Comparable<T>' where T is not compatible with the type of the class.

In order to facilitate enabling a compile-time error check, we are suppressing these existing instances. Once the compile-time error is enabled, we will file bugs to clean up any unfixed instances in [].

Note that this CL should result in no effective changes to the code, but the code as currently-written might contain a real bug. If you'd prefer to fix the bug now, please either reply with edits, or accept this CL then follow up with a change that fixes the underlying issue.

Tested:
    tap_presubmit: []    Some tests failed; test failures are believed to be unrelated to this CL

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=177836122

library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylist.java

@@ -29,9 +29,8 @@ import java.util.List;
  */
 public final class HlsMediaPlaylist extends HlsPlaylist {
 
-  /**
-   * Media segment reference.
-   */
+  /** Media segment reference. */
+  @SuppressWarnings("ComparableType")
   public static final class Segment implements Comparable<Long> {
 
     /**