Nbits: Add a couple more interesting sizes.

Previously, all tests with more than two levels came in powers of 2.  It's
usefule to check cases where we have a partially filled group at above the
second level.

test/include/test/nbits.h

@@ -70,6 +70,8 @@
     NB(63) \
     NB(64) \
     NB(65) \
+    NB(66) \
+    NB(67) \
     \
     NB(126) \
     NB(127) \
@@ -89,9 +91,20 @@
     NB(513) \
     NB(514) \
     \
+    NB(1022) \
+    NB(1023) \
     NB(1024) \
+    NB(1025) \
+    NB(1026) \
+    \
     NB(2048) \
+    \
+    NB(4094) \
+    NB(4095) \
     NB(4096) \
+    NB(4097) \
+    NB(4098) \
+    \
     NB(8192) \
     NB(16384)