CtxRed needs to expand more type synonyms

[quark17]

As mentioned in #310, a call to expandSyn in CtxRed had to be removed because of issues with TLM libraries. This code:

do -- XXX disable expanding of type synonyms until
   -- XXX failures with TLM instances are resolved
   -- XXX (vqs_extra, t1) <- expPrimTCons t0 (expandSyn t0)
   (vqs_extra, t1) <- expPrimTCons t0

should be replaced with this:

do (vqs_extra, t1) <- expPrimTCons (expandSyn t0)

An example can be found at bsc.typechecker/primtcons/ExpSizeOf_InstancesBaseSyn.bsv. Without expandSyn, this example fails to resolve a context:

Error: "ExpSizeOf_InstancesBaseSyn.bsv", line 6, column 10: (T0031)
  The provisos for this expression could not be resolved because there are no
  instances of the form:
    ExpSizeOf_InstancesBaseSyn::C#(ExpSizeOf_InstancesBaseSyn::S, 12)

This is bug 1729 in Bluespec Inc's pre-GitHub bug database.