Fix bugs found through fuzzing

Facade.h

@@ -29,12 +29,6 @@ struct Facade {
       const int64_t v[] = {version, version};
       facade->versioned.firstGeq(key, v, versionedIter, 2);
 
-      if (versionedIter[0] == versionedIter[1]) {
-        // No mutations intersect [begin, end)
-        facade->unversionedRead(begin, end, limit, reverse, result);
-        return result;
-      }
-
       // Make sure versionedIter[1] param1 is >= `end`
       if (versionedIter[1] != facade->versioned.end(version)) {
         auto m = *versionedIter[1];
@@ -43,6 +37,12 @@ struct Facade {
         }
       }
 
+      if (versionedIter[0] == versionedIter[1]) {
+        // No mutations intersect [begin, end)
+        facade->unversionedRead(begin, end, limit, reverse, result);
+        return result;
+      }
+
       static const uint8_t zero_[] = {0};
       static const String zero{zero_, 1};