Update HTTP status codes expected in failover scenarios.

library/core/src/main/java/com/google/android/exoplayer2/upstream/DefaultLoadErrorHandlingPolicy.java

@@ -72,9 +72,12 @@ public class DefaultLoadErrorHandlingPolicy implements LoadErrorHandlingPolicy {
     IOException exception = loadErrorInfo.exception;
     if (exception instanceof InvalidResponseCodeException) {
       int responseCode = ((InvalidResponseCodeException) exception).responseCode;
-      return responseCode == 404 // HTTP 404 Not Found.
+      return responseCode == 403 // HTTP 403 Forbidden.
+              || responseCode == 404 // HTTP 404 Not Found.
               || responseCode == 410 // HTTP 410 Gone.
               || responseCode == 416 // HTTP 416 Range Not Satisfiable.
+              || responseCode == 500 // HTTP 500 Internal Server Error.
+              || responseCode == 503 // HTTP 503 Service Unavailable.
           ? DEFAULT_TRACK_BLACKLIST_MS
           : C.TIME_UNSET;
     }

library/core/src/test/java/com/google/android/exoplayer2/upstream/DefaultLoadErrorHandlingPolicyTest.java

@@ -77,8 +77,8 @@ public final class DefaultLoadErrorHandlingPolicyTest {
   public void getExclusionDurationMsFor_dontExcludeUnexpectedHttpCodes() {
     InvalidResponseCodeException exception =
         new InvalidResponseCodeException(
-            500,
-            "Internal Server Error",
+            418,
+            "I'm a teapot",
             Collections.emptyMap(),
             new DataSpec(Uri.EMPTY),
             /* responseBody= */ Util.EMPTY_BYTE_ARRAY);