Disable "Forbid direct 'import triton'" check for vllm/triton_utils/importing.py in an extensible way (vllm-project#19783)

Signed-off-by: Andrew Feldman <afeldman@redhat.com>

Author: afeldman-nm

tools/check_triton_import.py

@@ -14,6 +14,12 @@
     "from vllm.triton_utils import tl, triton",
 }
 
+ALLOWED_FILES = {"vllm/triton_utils/importing.py"}
+
+
+def is_allowed_file(current_file: str) -> bool:
+    return current_file in ALLOWED_FILES
+
 
 def is_forbidden_import(line: str) -> bool:
     stripped = line.strip()
@@ -25,10 +31,14 @@ def parse_diff(diff: str) -> list[str]:
     violations = []
     current_file = None
     current_lineno = None
+    skip_allowed_file = False
 
     for line in diff.splitlines():
         if line.startswith("+++ b/"):
             current_file = line[6:]
+            skip_allowed_file = is_allowed_file(current_file)
+        elif skip_allowed_file:
+            continue
         elif line.startswith("@@"):
             match = re.search(r"\+(\d+)", line)
             if match: