benchmark: update gc1 and add new gc3 benchmark

extra/benchmark/gc1/gc1.factor

@@ -3,6 +3,6 @@
 USING: math sequences kernel ;
 IN: benchmark.gc1
 
-: gc1 ( -- ) 10 [ 600000 [ >bignum 1 + ] map drop ] times ;
+: gc1 ( -- ) 600000 [ >bignum 1 + ] map drop ;
 
 MAIN: gc1

extra/benchmark/gc3/authors.txt

@@ -0,0 +1 @@
+Slava Pestov

extra/benchmark/gc3/gc3.factor

@@ -0,0 +1,11 @@
+! Copyright (C) 2009 Slava Pestov.
+! See http://factorcode.org/license.txt for BSD license.
+USING: math.parser fry sequences kernel assocs hashtables ;
+IN: benchmark.gc3
+
+: gc3 ( -- )
+    1000000 iota
+    1000000 <hashtable>
+    '[ [ number>string ] keep _ set-at ] each ;
+
+MAIN: gc3