Fix peeking the end of the stream then reading it.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=133240502

library/src/main/java/com/google/android/exoplayer2/extractor/DefaultExtractorInput.java

@@ -125,7 +125,6 @@ public final class DefaultExtractorInput implements ExtractorInput {
       throws IOException, InterruptedException {
     ensureSpaceForPeek(length);
     int bytesPeeked = Math.min(peekBufferLength - peekBufferPosition, length);
-    peekBufferLength += length - bytesPeeked;
     while (bytesPeeked < length) {
       bytesPeeked = readFromDataSource(peekBuffer, peekBufferPosition, length, bytesPeeked,
           allowEndOfInput);
@@ -134,6 +133,7 @@ public final class DefaultExtractorInput implements ExtractorInput {
       }
     }
     peekBufferPosition += length;
+    peekBufferLength = Math.max(peekBufferLength, peekBufferPosition);
     return true;
   }