[Utils][WIP] Allow multiple run lines with the same check prefix

[jdoerfert]

Summary

Note: Test for this is missing

When we include generated functions we don't want to generate the same
functions for each run lines that share a prefix.

[jdoerfert]

D102558 is the proper solution for this

llvm/utils/UpdateTestChecks/common.py

for input_line_info in test_info.iterlines(output_lines):
     if line.lstrip().startswith(comment_string):
       m = CHECK_RE.match(line)
       if m and m.group(1) in prefix_set:
         continue
     output_lines.append(line.rstrip('\n'))
 
 def add_checks_at_end(output_lines, prefix_list, func_order,
                       comment_string, check_generator):
-  added = set()
+  printed = set()
   for prefix in prefix_list:
     prefixes = prefix[0]
     tool_args = prefix[1]
     for prefix in prefixes:
       for func in func_order[prefix]:
-        if added:
+        if (prefix, func) in printed:
+            continue
+        if printed:
           output_lines.append(comment_string)
-        added.add(func)
+        printed.add((prefix, func))
 
         # The add_*_checks routines expect a run list whose items are
         # tuples that have a list of prefixes as their first element and
         # tool command args string as their second element.  They output
         # checks for each prefix in the list of prefixes.  By doing so, it
         # implicitly assumes that for each function every run line will
         # generate something for that function.  That is not the case for
         # generated functions as some run lines might not generate them