hwasan: Fix an off-by-one error in PrintTagsAroundAddr.

[pcc]

Summary

Previously we were printing 16 rows of tags, not 17.

[eugenis]

LGTM

compiler-rt/trunk/lib/hwasan/hwasan_report.cpp

Printf(
       "Memory tags around the buggy address (one tag corresponds to %zd "
       "bytes):\n", kShadowAlignment);
 
   const uptr row_len = 16;  // better be power of two.
   const uptr num_rows = 17;
   tag_t *center_row_beg = reinterpret_cast<tag_t *>(
       RoundDownTo(reinterpret_cast<uptr>(tag_ptr), row_len));
   tag_t *beg_row = center_row_beg - row_len * (num_rows / 2);
-  tag_t *end_row = center_row_beg + row_len * (num_rows / 2);
+  tag_t *end_row = center_row_beg + row_len * ((num_rows + 1) / 2);
   InternalScopedString s(GetPageSizeCached() * 8);
   for (tag_t *row = beg_row; row < end_row; row += row_len) {
     s.append("%s", row == center_row_beg ? "=>" : "  ");
     for (uptr i = 0; i < row_len; i++) {
       s.append("%s", row + i == tag_ptr ? "[" : " ");
       s.append("%02x", row[i]);
       s.append("%s", row + i == tag_ptr ? "]" : " ");
     }