Remove C++17 canary

I had added a small snippet of no-op code here to make sure
this file builds in C++17 everywhere.

By now, C++17 is enabled and we use `if constexpr` in many
other places in base/, so remove that snippet again.

Bug: 752720
Change-Id: I5a10d515b43a65710a0bea132ede681313dda3b9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3383435
Commit-Queue: Nico Weber <thakis@chromium.org>
Auto-Submit: Nico Weber <thakis@chromium.org>
Reviewed-by: Hans Wennborg <hans@chromium.org>
Commit-Queue: Hans Wennborg <hans@chromium.org>
Cr-Commit-Position: refs/heads/main@{#958145}

base/strings/string_util.cc

@@ -33,11 +33,6 @@
 namespace base {
 
 bool IsWprintfFormatPortable(const wchar_t* format) {
-  // This snippet of code checks that we can build C++17 code.
-  // TODO(thakis): Remove this again in a bit.
-  if constexpr (constexpr int i = 0; i > 0) {
-  }
-
   for (const wchar_t* position = format; *position != '\0'; ++position) {
     if (*position == '%') {
       bool in_specification = true;