Add DwarfCompileUnit::BaseAddress to track the base address used by relative addressing in debug_ranges and debug_loc

This is one of a few steps to generalize range handling to include the
CU range (thus the CU's range list will be moved into the range list
list, losing track of the base address in the process), which means
generalizing ranges from both the skeleton and full unit under fission.

And... then I can used that generalized support for ranges in
fission+gmlt where there'll be a bunch more ranges in the skeleton.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221182 91177308-0d34-0410-b5e6-96231b3b80d8
[lit] Forward LD_PRELOAD to tests.

With this patch I can use asan to test the gold plugin without having
to build gold itself with asan.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221183 91177308-0d34-0410-b5e6-96231b3b80d8
[X86] Add debug print name for X86ISD::[US]MUL8. NFC-ish.

The opcodes were added in r220516, but I forgot to add the print names.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221185 91177308-0d34-0410-b5e6-96231b3b80d8