step 1: Test a hash-map with more than one entry.

All the existing tests in step 1 use empty or single-element hash-maps.
That avoids any dependency on the ordering of printed hash-maps, but it
does mean that some code paths (e.g. printing the space between hash-map
elements) aren't tested.  Add a test that creates a three-element
hash-map and uses some regexp trickery to check that all the right keys
and values come out.

tests/step1_read_print.mal

@@ -153,6 +153,8 @@ false
 ;=>{"a" {"b" {"c" 3}}}
 {  "a"  {"b"   {  "cde"     3   }  }}
 ;=>{"a" {"b" {"cde" 3}}}
+{"1" 1 "2" 2 "3" 3}
+;/{"([1-3])" \1 "(?!\1)([1-3])" \2 "(?!\1)(?!\2)([1-3])" \3}
 {  :a  {:b   {  :cde     3   }  }}
 ;=>{:a {:b {:cde 3}}}