And add a lit substitution for llvm-undname, as the comment says to

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337600 91177308-0d34-0410-b5e6-96231b3b80d8

Author: rnk

test/lit.cfg.py

@@ -147,7 +147,7 @@ def get_asan_rtlib():
     'llvm-modextract', 'llvm-nm', 'llvm-objcopy', 'llvm-objdump',
     'llvm-pdbutil', 'llvm-profdata', 'llvm-ranlib', 'llvm-readobj',
     'llvm-rtdyld', 'llvm-size', 'llvm-split', 'llvm-strings', 'llvm-strip', 'llvm-tblgen',
-    'llvm-c-test', 'llvm-cxxfilt', 'llvm-xray', 'yaml2obj', 'obj2yaml',
+    'llvm-undname', 'llvm-c-test', 'llvm-cxxfilt', 'llvm-xray', 'yaml2obj', 'obj2yaml',
     'yaml-bench', 'verify-uselistorder',
     'bugpoint', 'llc', 'llvm-symbolizer', 'opt', 'sancov', 'sanstats'])