Resubmit D85085 after fixing the tests that were failing.

D85085 was pushed earlier but broke tests on mac and win:
http://lab.llvm.org:8080/green/job/clang-stage1-RA/21182/consoleFull#-706149783d489585b-5106-414a-ac11-3ff90657619c

Recommitting it after adding mtriple to the llc commands.

Emit correct location lists with basic block sections.

This patch addresses multiple things:

1) It ensures that const_value is emitted when possible with basic block
   sections.
2) It emits location lists such that the labels are always within the
   section boundary.
3) It fixes a bug when the parameter is first used in a non-entry block
   which is in a different section from the entry block.

Differential Revision: https://reviews.llvm.org/D85085