Revert commit 101503 (johannes), in the hope of fixing the dragonegg build,

see http://google1.osuosl.org:8011/builders/dragonegg-x86_64-linux/builds/693
Original commit text:
Use a ValueMap not a std::map for the reason indicated
in the comment.  This was causing nondeterministic changes
in inlining decisions.

llvm-svn: 101525