use raw_ostream instead of std::ostream.  Among other goodness,
this speeds up llvm-dis of kc++ with a release build from 0.85s
to 0.49s (88% faster).

Other interesting changes:
 1) This makes Value::print be non-virtual.
 2) AP[S]Int and ConstantRange can no longer print to ostream directly, 
    use raw_ostream instead.
 3) This fixes a bug in raw_os_ostream where it didn't flush itself 
    when destroyed.
 4) This adds a new SDNode::print method, instead of only allowing "dump".


A lot of APIs have both std::ostream and raw_ostream versions, it would
be useful to go through and systematically anihilate the std::ostream 
versions.

This passes dejagnu, but there may be minor fallout, plz let me know if
so and I'll fix it.

llvm-svn: 55263