Remove dummy PRIszX macros for formatting

Size specifiers are no longer needed now that we use typesafe tinyformat
for string formatting, instead of the system's sprintf.

No functional changes.

This continues the work in #3735.

src/util.h

@@ -44,18 +44,6 @@ static const int64_t CENT = 1000000;
 #define UEND(a)             ((unsigned char*)&((&(a))[1]))
 #define ARRAYLEN(array)     (sizeof(array)/sizeof((array)[0]))
 
-/* Format characters for (s)size_t, ptrdiff_t.
- *
- * Define these as empty as the tinyformat-based formatting system is
- * type-safe, no special format characters are needed to specify sizes.
- */
-#define PRIszx    "x"
-#define PRIszu    "u"
-#define PRIszd    "d"
-#define PRIpdx    "x"
-#define PRIpdu    "u"
-#define PRIpdd    "d"
-
 // This is needed because the foreach macro can't get over the comma in pair<t1, t2>
 #define PAIRTYPE(t1, t2)    std::pair<t1, t2>