Strange error in test/inference.jl

Internally IdDicts are only used early in the bootstrap.  All other
instances of ObjectIdDict use my new implementation.

Skipping CIs as I expect tests to fail.  I will force push a working
commit onto this tomorrow.

[ci skip]
[av skip]
[bsd skip]

?module works
?sin does not

rehashing the meta-dicts fixes it

for m in Base.Docs.modules
    Base.rehash!(Base.Docs.meta(m))
end

Simlarly, there was a rehashing in serialize.jl which was fixed going
ObjectIdDict->IdDict.  But with the doc-system that did not help.

Skipping some CIs to save resources:
[ci skip]
[av skip]
[bsd skip]