Quick fix for the flutter build.

Reverting the breaking part of
https://dart-review.googlesource.com/c/sdk/+/84542. I'll mail a proper
fix for this later.

Tested locally by building the flutter engine.

Bug: https://github.com/dart-lang/sdk/issues/35187
Change-Id: I1dbde39b4a8b437f711ad82c98790de87f28add5
Reviewed-on: https://dart-review.googlesource.com/c/84580
Reviewed-by: Siva Annamalai <asiva@google.com>
Commit-Queue: Liam Appelbe <liama@google.com>
diff --git a/runtime/include/bin/dart_io_api.h b/runtime/include/bin/dart_io_api.h
index e194f7a..07a384c 100644
--- a/runtime/include/bin/dart_io_api.h
+++ b/runtime/include/bin/dart_io_api.h
@@ -5,7 +5,7 @@
 #ifndef RUNTIME_INCLUDE_BIN_DART_IO_API_H_
 #define RUNTIME_INCLUDE_BIN_DART_IO_API_H_
 
-#include "dart_tools_api.h"
+#include "include/dart_tools_api.h"
 
 namespace dart {
 namespace bin {