deps: fix CLEAR_HASH macro to be usable as a single statement

Apply unreleased (as of zlib v1.2.11) patch from upstream:
- 38e8ce32af

Original commit message:
  Fix CLEAR_HASH macro to be usable as a single statement.

  As it is used in deflateParams().

PR-URL: https://github.com/nodejs/node/pull/11616
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

deps/zlib/deflate.c

@@ -190,8 +190,11 @@ local const config configuration_table[10] = {
  * prev[] will be initialized on the fly.
  */
 #define CLEAR_HASH(s) \
+    do { \
         s->head[s->hash_size-1] = NIL; \
-    zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
+        zmemzero((Bytef *)s->head, \
+                 (unsigned)(s->hash_size-1)*sizeof(*s->head)); \
+    } while (0)
 
 /* ===========================================================================
  * Slide the hash table when sliding the window down (could be avoided with 32