Revert most of r215810, which is no longer needed

Now that we no longer add mappings when there are no local entities,
there is no need to always bump the size of the tables that correspond
to ContinuousRangeMaps.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@220208 91177308-0d34-0410-b5e6-96231b3b80d8