Fix dx test 034.

- Test 034 requires that a dex file is dumped in a human readable form
even if the dex file does not contain ClassDef.
Consequently, the command line behavior is modified to satisfy this requirement.

(cherry-pick from commit 64f4aad1e6ef58b29f860b59512ca1a676ac6eb8)

Change-Id: Id64b563745db2b22ec98fba9be25413192c07719