Allocate the threadData array directly

The threadData array (formerly named tdArray) has a fixed size (i.e.,
the array does not grow or shrink while in use), so we can allocate the
array directly. It is not necessary to define the array as avifArray.

(cherry picked from commit c74189f9123bc01139ed316970f673394a57e814)

src/reformat.c

diff --git a/src/reformat.c b/src/reformat.c
index da6a73d..5e6088c 100644
--- a/src/reformat.c
+++ b/src/reformat.c
@@ -1544,11 +1544,12 @@
         return avifImageYUVToRGBImpl(image, rgb, &state, alphaMultiplyMode);
     }
 
-    AVIF_ARRAY_DECLARE(YUVToRGBThreadDataArray, YUVToRGBThreadData, threadData);
-    YUVToRGBThreadDataArray tdArray;
-    if (!avifArrayCreate(&tdArray, sizeof(YUVToRGBThreadData), jobs)) {
+    const size_t byteCount = sizeof(YUVToRGBThreadData) * jobs;
+    YUVToRGBThreadData * threadData = avifAlloc(byteCount);
+    if (!threadData) {
         return AVIF_RESULT_OUT_OF_MEMORY;
     }
+    memset(threadData, 0, byteCount);
     int rowsPerJob = image->height / jobs;
     if (rowsPerJob % 2) {
         ++rowsPerJob;
@@ -1557,7 +1558,7 @@
     int startRow = 0;
     uint32_t i;
     for (i = 0; i < jobs; ++i, startRow += rowsPerJob) {
-        YUVToRGBThreadData * tdata = &tdArray.threadData[i];
+        YUVToRGBThreadData * tdata = &threadData[i];
         const avifCropRect rect = { .x = 0, .y = startRow, .width = image->width, .height = (i == jobs - 1) ? rowsForLastJob : rowsPerJob };
         if (avifImageSetViewRect(&tdata->image, image, &rect) != AVIF_RESULT_OK) {
             tdata->result = AVIF_RESULT_REFORMAT_FAILED;
@@ -1581,11 +1582,11 @@
     }
     // If above loop ran successfully, Run the first job in the current thread.
     if (i == jobs) {
-        avifImageYUVToRGBThreadWorker(&tdArray.threadData[0]);
+        avifImageYUVToRGBThreadWorker(&threadData[0]);
     }
     avifResult result = AVIF_RESULT_OK;
     for (i = 0; i < jobs; ++i) {
-        YUVToRGBThreadData * tdata = &tdArray.threadData[i];
+        YUVToRGBThreadData * tdata = &threadData[i];
         if (tdata->threadCreated && !avifJoinYUVToRGBThread(tdata)) {
             result = AVIF_RESULT_REFORMAT_FAILED;
         }
@@ -1593,7 +1594,7 @@
             result = tdata->result;
         }
     }
-    avifArrayDestroy(&tdArray);
+    avifFree(threadData);
     return result;
 }