Fix a crash in heuristic memory mapping.

Commit 712ed9b changed the way that the Sufami
Turbo base cartridge was detected, but it caused crashes. Apparently the way we
were converting the binary ROM data to a string for comparison, was actually
calling the wrong `string` constructor. Let's more explicitly create a
string_view instead of hoping for the compiler to pick a suitable constructor
chain.

bsnes/heuristics/super-famicom.cpp

@@ -271,7 +271,7 @@ auto SuperFamicom::board() const -> string {
   //Bishoujo Senshi Sailor Moon SuperS - Fuwafuwa Panic (Japan)
   //so we identify it with this embedded string
   string sufamiSignature = "BANDAI SFC-ADX";
-  if (string(data.view(0, sufamiSignature.length())) == sufamiSignature) board.append("ST-", mode);
+  if (string_view(data.data(), sufamiSignature.length()) == sufamiSignature) board.append("ST-", mode);
 
   //this game's title ovewrites the map mode with '!' (0x21), but is a LOROM game
   if(title() == "YUYU NO QUIZ DE GO!GO") mode = "LOROM-";