Fixes a minor valgrind issue in the chunk_info test (#675)

* Fixes a minor valgrind issue in the chunk_info test

The chunk_info test incorrectly set the number of bytes in a compressed
buffer, which caused valgrind to complain about writing uninitialized
bytes.

* Committing clang-format changes

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

test/chunk_info.c

@@ -449,7 +449,7 @@ verify_idx_nchunks(hid_t dset, hid_t dspace, H5D_chunk_index_t exp_idx_type, hsi
  * Return:      Success:    SUCCEED
  *              Failure:    FAIL
  *
- * Note:        Note that the dataspace argument in these new functions are
+ * Note:        Note that the dataspace argument in these new functions is
  *              currently not used.  The functionality involved the dataspace
  *              will be implemented in the next version.
  *
@@ -486,10 +486,10 @@ test_get_chunk_info_highest_v18(hid_t fapl)
     hsize_t  offset[2]    = {0, 0};                       /* Offset coordinates of a chunk */
 #ifdef H5_HAVE_FILTER_DEFLATE
     const Bytef *z_src = (const Bytef *)(direct_buf);
-    Bytef *      z_dst; /*destination buffer */
+    Bytef *      z_dst; /* Destination buffer */
     uLongf       z_dst_nbytes = (uLongf)DEFLATE_SIZE_ADJUST(CHK_SIZE);
     uLong        z_src_nbytes = (uLong)CHK_SIZE;
-#endif                             /* end H5_HAVE_FILTER_DEFLATE */
+#endif
     void *  inbuf      = NULL;     /* Pointer to new buffer */
     hsize_t chunk_size = CHK_SIZE; /* Size of a chunk, can be compressed or not */
     hsize_t ii, jj;                /* Array indices */
@@ -544,14 +544,15 @@ test_get_chunk_info_highest_v18(hid_t fapl)
     /* Allocate input (compressed) buffer */
     inbuf = HDmalloc(z_dst_nbytes);
 
-    /* Set chunk size to the compressed chunk size and the chunk point
-       to the compressed data chunk */
-    chunk_size = (hsize_t)z_dst_nbytes;
-    z_dst      = (Bytef *)inbuf;
+    /* zlib-friendly alias for the input buffer */
+    z_dst = (Bytef *)inbuf;
 
     /* Perform compression from the source to the destination buffer */
     ret = compress2(z_dst, &z_dst_nbytes, z_src, z_src_nbytes, aggression);
 
+    /* Set the chunk size to the compressed chunk size */
+    chunk_size = (hsize_t)z_dst_nbytes;
+
     /* Check for various zlib errors */
     if (Z_BUF_ERROR == ret) {
         HDfprintf(stderr, "overflow");