Suppress warnings emitted by Checker Framework version 2.11.1

More information:
https://docs.google.com/document/d/16tpK6aXqN68PvTyvt4siM-m7f0NXi_8xEeitLDzr8xY/edit?usp=sharing

Tested:
    tap_presubmit: http://test/OCL:278683723:BASE:278762656:1573036487314:924e1b0b
    Some tests failed; test failures are believed to be unrelated to this CL
PiperOrigin-RevId: 279034739

library/core/src/main/java/com/google/android/exoplayer2/extractor/mp4/PsshAtomUtil.java

@@ -49,7 +49,8 @@ public final class PsshAtomUtil {
    * @param data The scheme specific data.
    * @return The PSSH atom.
    */
-  @SuppressWarnings("ParameterNotNullable")
+  // dereference of possibly-null reference keyId
+  @SuppressWarnings({"ParameterNotNullable", "nullness:dereference.of.nullable"})
   public static byte[] buildPsshAtom(
       UUID systemId, @Nullable UUID[] keyIds, @Nullable byte[] data) {
     int dataLength = data != null ? data.length : 0;