Defer extractor init until after sniff

Instead of doing it immediately after sniff success.
This prevents some extractor implementations from
outputting formats during the "sniffing" advance.

Bug: 154120292
Test: atest CtsMediaParserTestCases
Change-Id: I4f3349a8053d371cd06beaf24bd9745da0a4a093
1 file changed
tree: 114b6a8506983be74c4d93eb1cd5a848bd45954e
  1. apex/