Fix check for missing profile/level

SparseIntArray.get(key) defaults to zero for missing keys (the null check was
left over from when a Map was used).

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=196957452

library/core/src/main/java/com/google/android/exoplayer2/mediacodec/MediaCodecUtil.java

@@ -482,13 +482,13 @@ public final class MediaCodecUtil {
       return null;
     }
 
-    Integer profile = AVC_PROFILE_NUMBER_TO_CONST.get(profileInteger);
-    if (profile == null) {
+    int profile = AVC_PROFILE_NUMBER_TO_CONST.get(profileInteger, -1);
+    if (profile == -1) {
       Log.w(TAG, "Unknown AVC profile: " + profileInteger);
       return null;
     }
-    Integer level = AVC_LEVEL_NUMBER_TO_CONST.get(levelInteger);
-    if (level == null) {
+    int level = AVC_LEVEL_NUMBER_TO_CONST.get(levelInteger, -1);
+    if (level == -1) {
       Log.w(TAG, "Unknown AVC level: " + levelInteger);
       return null;
     }