fuzz_utils.cc: fix build error w/WEBP_REDUCE_SIZE

Correct (void) variable names.

Bug: webp:380121350
Change-Id: I3ce8a4d34f60f9ec0a467fcb5958b0b7a2edabc9

tests/fuzzer/fuzz_utils.cc

@@ -76,9 +76,8 @@ int CropOrScale(WebPPicture* const pic, const CropOrScaleParams& params) {
     }
   }
 #else   // defined(WEBP_REDUCE_SIZE)
-  (void)data;
-  (void)size;
-  (void)bit_pos;
+  (void)pic;
+  (void)params;
 #endif  // !defined(WEBP_REDUCE_SIZE)
   return 1;
 }

tests/fuzzer/mux_demux_api_fuzzer.cc

@@ -24,7 +24,7 @@
 
 namespace {
 
-void MuxDemuxApiTest(std::string_view data_in, bool mux) {
+void MuxDemuxApiTest(std::string_view data_in, bool use_mux_api) {
   const size_t size = data_in.size();
   WebPData webp_data;
   WebPDataInit(&webp_data);
@@ -34,7 +34,7 @@ void MuxDemuxApiTest(std::string_view data_in, bool mux) {
   // Extracted chunks and frames are not processed or decoded,
   // which is already covered extensively by the other fuzz targets.
 
-  if (mux) {
+  if (use_mux_api) {
     // Mux API
     WebPMux* mux = WebPMuxCreate(&webp_data, size & 2);
     if (!mux) return;