[mlir] Tidy uses of llvm::raw_stream_ostream (NFC)

As specified in the docs,
1) raw_string_ostream is always unbuffered and
2) the underlying buffer may be used directly

( 65b13610a5226b84889b923bae884ba395ad084d for further reference )

* Don't call raw_string_ostream::flush(), which is essentially a no-op.
* Avoid unneeded calls to raw_string_ostream::str(), to avoid excess indirection.

1 files changed, 1 insertions, 1 deletions

diff --git a/mlir/lib/Debug/Observers/ActionProfiler.cpp b/mlir/lib/Debug/Observers/ActionProfiler.cpp
index 07bf9fd0ccc7..a6b7d5e18aa0 100644
--- a/mlir/lib/Debug/Observers/ActionProfiler.cpp
+++ b/mlir/lib/Debug/Observers/ActionProfiler.cpp
@@ -58,6 +58,6 @@ void ActionProfiler::print(const ActionActiveStack *action,
   if (printComma)
     os << ",\n";
   printComma = true;
-  os << event.str();
+  os << str;
   os.flush();
 }