adds simple tests for +muk and +mum

tests/sys/hoon/hashes.hoon

@@ -0,0 +1,56 @@
+/+  *test
+|%
+++  test-muk
+  ;:  weld
+    %+  expect-eq
+      !>  0xfaf6.cdb3
+      !>  (muk 1.234 13 'Hello, world!')
+    ::
+    %+  expect-eq
+      !>  0xbf50.5788
+      !>  (muk 4.321 13 'Hello, world!')
+    ::
+    %+  expect-eq
+      !>  0xf2c.c00b
+      !>  (muk 1.234 0 0)
+    ::
+    %+  expect-eq
+      !>  0x8905.ac28
+      !>  (muk 1.234 28 (crip (reap 28 'x')))
+    ::
+    %+  expect-eq
+      !>  0x566f.7173
+      !>  (muk 0xcafe.babe 16 (dec (bex 128)))
+  ==
+::
+++  test-mum
+  ;:  weld
+    %+  expect-eq
+      !>  0x4d44.1035
+      !>  (mum 'Hello, world!')
+    ::
+    %+  expect-eq
+      !>  0x79ff.04e8
+      !>  (mum 0)
+    ::
+    %+  expect-eq
+      !>  0x64df.da5c
+      !>  (mum (crip (reap 28 'x')))
+    ::
+    %+  expect-eq
+      !>  0x389c.a03a
+      !>  (mum [0 0])
+    ::
+    %+  expect-eq
+      !>  0x389c.a03a
+      !>  (mum [1 1])
+    ::
+    %+  expect-eq
+      !>  0x5258.a6c0
+      !>  (mum [0 (bex 32)])
+    ::
+    %+  expect-eq
+      !>  0x2ad3.9968
+      !>  (mum [(dec (bex 128)) 1])
+  ==
+--