[llvm] fix(llvm/**.py): fix invalid escape sequences (PR #94035)

[Nikita Popov via llvm-commits]

================
@@ -17,24 +17,24 @@ def remove_prefix(i, d=0):
             p = r.group(1)
             s = re.sub("=" + p + ",", "=", s)
             s = re.sub("," + p + "([, \n])", "\\1", s)
-            s = re.sub("\s+-?-check-prefix=" + p + "([ \n])", "\\1", s)
+            s = re.sub("\\s+-?-check-prefix=" + p + "([ \n])", "\\1", s)
         else:
             s = re.sub(
-                "-?-check-prefixes=([\w-]+)(\Z|[ \t\n])", "--check-prefix=\\1\\2", s
+                "-?-check-prefixes=([\\w-]+)(\\Z|[ \t\n])", "--check-prefix=\\1\\2", s
----------------
nikic wrote:

```suggestion
               r "-?-check-prefixes=([\w-]+)(\Z|[ \t\n])", "--check-prefix=\\1\\2", s
```

https://github.com/llvm/llvm-project/pull/94035