fixed regression test assert

optLdm->offset might be == 0 in invalid case.
Only use STORE_OFFSET() after validating it's a correct case.

lib/compress/zstd_compress_internal.h

@@ -565,7 +565,9 @@ MEM_STATIC int ZSTD_literalsCompressionIsDisabled(const ZSTD_CCtx_params* cctxPa
  *  Only called when the sequence ends past ilimit_w, so it only needs to be optimized for single
  *  large copies.
  */
-static void ZSTD_safecopyLiterals(BYTE* op, BYTE const* ip, BYTE const* const iend, BYTE const* ilimit_w) {
+static void
+ZSTD_safecopyLiterals(BYTE* op, BYTE const* ip, BYTE const* const iend, BYTE const* ilimit_w)
+{
     assert(iend > ilimit_w);
     if (ip <= ilimit_w) {
         ZSTD_wildcopy(op, ip, ilimit_w - ip, ZSTD_no_overlap);