Drop unnecessary depwarn + fix Turing tests (#433)

This PR fixes the performance regressions seen for `Emcee` in TuringLang/Turing.jl#1900.

@yebai @devmotion This should be an easy merge.

Author: torfjelde

Project.toml

@@ -1,6 +1,6 @@
 name = "DynamicPPL"
 uuid = "366bfd00-2699-11ea-058f-f148b4cae6d8"
-version = "0.21.2"
+version = "0.21.3"
 
 [deps]
 AbstractMCMC = "80f14c24-f653-4e6a-9b94-39d6b0f70001"

src/varinfo.jl

@@ -759,10 +759,6 @@ function _link!(vi::UntypedVarInfo, spl::Sampler)
     end
 end
 function _link!(vi::TypedVarInfo, spl::AbstractSampler)
-    Base.depwarn(
-        "`link!(varinfo, sampler)` is deprecated, use `link!!(varinfo, sampler, model)` instead.",
-        :link!,
-    )
     return _link!(vi, spl, Val(getspace(spl)))
 end
 function _link!(vi::TypedVarInfo, spl::AbstractSampler, spaceval::Val)