MSVC also doesn't like casting lambdas with `+'. Sigh.

Change-Id: I0ac3abb775b7b69595dedc151de0d5ba79b74942
Reviewed-on: https://code-review.googlesource.com/c/re2/+/51975
Reviewed-by: Paul Wankadia <junyer@google.com>
diff --git a/re2/testing/dfa_test.cc b/re2/testing/dfa_test.cc
index 11cc1e0..9d8b533 100644
--- a/re2/testing/dfa_test.cc
+++ b/re2/testing/dfa_test.cc
@@ -31,10 +31,10 @@
 
 struct SetHooks {
   SetHooks() {
-    hooks::SetDFAStateCacheResetHook(+[](const hooks::DFAStateCacheReset&) {
+    hooks::SetDFAStateCacheResetHook([](const hooks::DFAStateCacheReset&) {
       ++state_cache_resets;
     });
-    hooks::SetDFASearchFailureHook(+[](const hooks::DFASearchFailure&) {
+    hooks::SetDFASearchFailureHook([](const hooks::DFASearchFailure&) {
       ++search_failures;
     });
   }