cc1_main: Do not print statistics twice in -disable_free mode.

llvm statistics are currently printed when the destructor of a "static
ManagedStatic<StatisticInfo> StatInfo" in llvm runs.  This destructor
currently runs in each case as part of llvm_shutdown() which is run even
in disable_free mode as part of main(). I assume that this hasn't always
been the case.

Removing the special code here avoids the statistics getting printed
twice.

Differential Revision: http://reviews.llvm.org/D21338

llvm-svn: 272820