Revert "Rewrite the cached map used for locating the most precise DIE among...

Revert "Rewrite the cached map used for locating the most precise DIE among inlined subroutines for a given address."

Seeing some inlining missing in internal uses of symbolizer. I'll work
on a reproduction, tests, improvements & recommit as soon as possible.

(Chandler would like it to be known that this improvement did make
check-llvm 4x faster... - so there's certainly some fairly good
motivation to push on fixing/figuring this out & getting it back in)

This reverts commit r321345.

llvm-svn: 324981