Fix memory leak for hashing with nondeterministic collations.

Backpatch through 12, where nondeterministic collations were
introduced (5e1963fb76).

Backpatch-through: 12

src/backend/access/hash/hashfunc.c

@@ -303,6 +303,7 @@ hashtext(PG_FUNCTION_ARGS)
 			buf = palloc(bsize);
 			ucol_getSortKey(mylocale->info.icu.ucol,
 							uchar, ulen, buf, bsize);
+			pfree(uchar);
 
 			result = hash_any(buf, bsize);
 
@@ -360,6 +361,7 @@ hashtextextended(PG_FUNCTION_ARGS)
 			buf = palloc(bsize);
 			ucol_getSortKey(mylocale->info.icu.ucol,
 							uchar, ulen, buf, bsize);
+			pfree(uchar);
 
 			result = hash_any_extended(buf, bsize, PG_GETARG_INT64(1));
 

src/backend/utils/adt/varchar.c

@@ -1031,6 +1031,7 @@ hashbpchar(PG_FUNCTION_ARGS)
 			buf = palloc(bsize);
 			ucol_getSortKey(mylocale->info.icu.ucol,
 							uchar, ulen, buf, bsize);
+			pfree(uchar);
 
 			result = hash_any(buf, bsize);
 
@@ -1092,6 +1093,7 @@ hashbpcharextended(PG_FUNCTION_ARGS)
 			buf = palloc(bsize);
 			ucol_getSortKey(mylocale->info.icu.ucol,
 							uchar, ulen, buf, bsize);
+			pfree(uchar);
 
 			result = hash_any_extended(buf, bsize, PG_GETARG_INT64(1));