for plain inherits this is really just a stylistic choice, but for
inherit-from it actually fixes an exponential size increase problem
during expr printing (as may happen during assertion failure reporting,
on during duplicate attr detection in the parser)
(cherry picked from commit ecf8b12d60ad2929f9998666cf0966475b91e291)
Change-Id: Ie55f0cb01a37e766414c31f8d40f51c2c7d106b0
this also has the effect of sorting let bindings lexicographically
rather than by symbol creation order as was previously done, giving a
better canonicalization in the process.
(cherry picked from commit 6c08fba533ef31cad2bdc03ba72ecf58dc8ee5a0)
Change-Id: Ia887f629305645bb8a165fbbc0d32e620912595a
