[vm/reload] Ensure FileModifiedCallback can handle uris on Windows.

Bug: #49634
Change-Id: I65b5c2a0559fdc51c003ffa6e955008850137a1c
TEST=bad_reload_test on Windows
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/277044
Commit-Queue: Alexander Aprelev <aam@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>

runtime/bin/main.cc

@@ -938,18 +938,18 @@ static void ServiceStreamCancelCallback(const char* stream_id) {
 }
 
 static bool FileModifiedCallback(const char* url, int64_t since) {
-  if (strncmp(url, "file:///", 8) != 0) {
+  auto path = File::UriToPath(url);
+  if (path == nullptr) {
     // If it isn't a file on local disk, we don't know if it has been
     // modified.
     return true;
   }
   int64_t data[File::kStatSize];
-  File::Stat(NULL, url + 7, data);
+  File::Stat(NULL, path.get(), data);
   if (data[File::kType] == File::kDoesNotExist) {
     return true;
   }
-  bool modified = data[File::kModifiedTime] > since;
-  return modified;
+  return data[File::kModifiedTime] > since;
 }
 
 static void EmbedderInformationCallback(Dart_EmbedderInformation* info) {