Use llvm::is_contained (NFC)

GitOrigin-RevId: 360c1111e358c4c7e8591953ce9548d60c9410a6
diff --git a/include/polly/ScopInfo.h b/include/polly/ScopInfo.h
index 404edc8..b89d1be 100644
--- a/include/polly/ScopInfo.h
+++ b/include/polly/ScopInfo.h
@@ -1359,8 +1359,7 @@
     if (!Inst)
       return false;
     if (isBlockStmt())
-      return std::find(Instructions.begin(), Instructions.end(), Inst) !=
-             Instructions.end();
+      return llvm::is_contained(Instructions, Inst);
     return represents(Inst->getParent());
   }