Simplification and size reduction to the printf logic. Remove the bFlags

parameter from sqlite3VXPrintf() and sqlite3XPrintf().  Use sqlite3XPrintf()
instead of sqlite3_snprintf() for rendering P4 values in EXPLAIN output.

FossilOrigin-Name: 0bdb41c45aa1cc8e5c136aaa6605d54b401483bd

src/func.c

@@ -239,7 +239,8 @@ static void printfFunc(
     x.nUsed = 0;
     x.apArg = argv+1;
     sqlite3StrAccumInit(&str, db, 0, 0, db->aLimit[SQLITE_LIMIT_LENGTH]);
-    sqlite3XPrintf(&str, SQLITE_PRINTF_SQLFUNC, zFormat, &x);
+    str.printfFlags = SQLITE_PRINTF_SQLFUNC;
+    sqlite3XPrintf(&str, zFormat, &x);
     n = str.nChar;
     sqlite3_result_text(context, sqlite3StrAccumFinish(&str), n,
                         SQLITE_DYNAMIC);