Fix documentation and logging in LongArray.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=120693278

library/src/main/java/com/google/android/exoplayer/util/LongArray.java

@@ -56,11 +56,11 @@ public final class LongArray {
    * @param index The index.
    * @return The corresponding value.
    * @throws IndexOutOfBoundsException If the index is less than zero, or greater than or equal to
-   *     {@link #size()}
+   *     {@link #size()}.
    */
   public long get(int index) {
     if (index < 0 || index >= size) {
-      throw new IndexOutOfBoundsException("Invalid size " + index + ", size is " + size);
+      throw new IndexOutOfBoundsException("Invalid index " + index + ", size is " + size);
     }
     return values[index];
   }