Revert "hash-sets,hashtables: make it so the array backing the hash is non-empty"

This reverts commit 6f10f06c27.

core/hash-sets/hash-sets.factor

@@ -10,10 +10,7 @@ IN: hash-sets
 TUPLE: hash-set
     { count array-capacity }
     { deleted array-capacity }
-    { array array initial: {
-          T{ tombstone } T{ tombstone } T{ tombstone } T{ tombstone }
-      }
-    } ;
+    { array array } ;
 
 <PRIVATE
 

core/hashtables/hashtables-tests.factor

@@ -1,11 +1,5 @@
-USING: accessors arrays assocs continuations fry hashtables
-hashtables.private kernel make math memory namespaces sequences
-tools.test ;
-
-! hash@
-{ 18 } [
-    77 20 f <array> hash@
-] unit-test
+USING: accessors assocs continuations fry hashtables kernel make
+math namespaces sequences tools.test ;
 
 { H{ } } [ { } [ dup ] H{ } map>assoc ] unit-test
 
@@ -188,14 +182,5 @@ H{ } "x" set
 
 { 1 } [ 2 "h" get at ] unit-test
 
-! Previously this could break as hashtable new created a backing an
-! empty backing array and the code assumed its length was > 0.
-{ f f } [
-    compact-gc 77 hashtable new [ clone ] change-array at*
-] unit-test
-
 ! Random test case
-{ "A" } [
-    100 iota [ dup ] H{ } map>assoc 32 over
-    delete-at "A" 32 pick set-at 32 of
-] unit-test
+{ "A" } [ 100 iota [ dup ] H{ } map>assoc 32 over delete-at "A" 32 pick set-at 32 of ] unit-test

core/hashtables/hashtables.factor

@@ -4,16 +4,10 @@ USING: accessors arrays assocs kernel kernel.private math
 math.private sequences sequences.private slots.private vectors ;
 IN: hashtables
 
-! Required because the hashtable definition references tombstone.
-<PRIVATE PRIVATE>
-
 TUPLE: hashtable
     { count array-capacity }
     { deleted array-capacity }
-    { array array initial: {
-          T{ tombstone } T{ tombstone } T{ tombstone } T{ tombstone }
-      }
-    } ;
+    { array array } ;
 
 <PRIVATE