Rework PlanTranslatorTorchscript so it doesn't strip Parameters

[Syzygianinfern0]

Resolve Conficts, merge with master

It turns out jit.trace() strips Parameters out of the tensor chain,
which causes issues with fix_precision. Don't fully understand why
jit.trace() does that, but operating on a copy of the original Plan
avoid mutating the original State tensors, which fixes the issue.
@karlhigley #3375

[codecov]

Codecov Report

Merging #3376 into master will decrease coverage by 0.03%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #3376      +/-   ##
==========================================
- Coverage   94.71%   94.68%   -0.02%     
==========================================
  Files         151      151              
  Lines       16294    16291       -3     
==========================================
- Hits        15431    15424       -7     
- Misses        863      867       +4     

Impacted Files	Coverage Δ
syft/execution/translation/torchscript.py	100.00% <100.00%> (ø)
syft/generic/pointers/object_pointer.py	78.20% <0.00%> (-3.75%)	⬇️
syft/execution/state.py	90.27% <0.00%> (+0.89%)	⬆️

[karlhigley]

test_fit is known to be flaky. 😢