patch(compiler): put local templates into the compiler engine struct

[ecrupper]

Ref: #916

[codecov]

Codecov Report

Merging #917 (26859ce) into v0.20.1 (af55191) will increase coverage by 0.10%.
The diff coverage is 34.61%.

@@             Coverage Diff             @@
##           v0.20.1     #917      +/-   ##
===========================================
+ Coverage    71.47%   71.57%   +0.10%     
===========================================
  Files          304      304              
  Lines        12450    12438      -12     
===========================================
+ Hits          8899     8903       +4     
+ Misses        3120     3106      -14     
+ Partials       431      429       -2     

Files Changed	Coverage Δ
compiler/native/expand.go	71.23% <0.00%> (-2.96%)	⬇️
compiler/native/compile.go	67.91% <100.00%> (+4.25%)	⬆️
compiler/native/native.go	86.27% <100.00%> (+0.56%)	⬆️

[KellyMerrick]

lgtm