[lit] Don't match tool names within new PM's <> markers

For example, stop expanding 'opt' in -passes='require<opt-remark-emit>'.

llvm-svn: 276707

llvm/test/lit.cfg

@@ -220,7 +220,7 @@ else:
 # The regex is a pre-assertion to avoid matching a preceding
 # dot, hyphen, carat, or slash (.foo, -foo, etc.).  Some patterns
 # also have a post-assertion to not match a trailing hyphen (foo-).
-NOJUNK = r"(?<!\.|-|\^|/)"
+NOJUNK = r"(?<!\.|-|\^|/|<)"
 
 
 def find_tool_substitution(pattern):