Support static arrays with reverse Enzyme

[gdalle]

Fixes #558, fixes #583 (but without tests for now, see #586).

Versions

• Bump DI to v0.6.14

DI extensions

• Enzyme: some modifications to reverse mode with out-of-place functions
  • For pullback and gradient, guess input and return activity with Enzyme.guess_activity.
  • If the derivative output is nothing, retrieve the values from the provided shadows, otherwise use that output.
  • Deactivate Enzyme's native reverse jacobian because it uses setindex!.

DI tests

• Enzyme: test on static arrays for out-of-place scenarios $\cap$ out-of-place functions

---

Related:

• Choosing between Active and Duplicated EnzymeAD/Enzyme.jl#1948
• Enzyme.gradient allocates on SVector EnzymeAD/Enzyme.jl#1968

Ping @ExpandingMan.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.58%. Comparing base (94f9bc5) to head (4372a4f).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #585      +/-   ##
==========================================
+ Coverage   97.54%   97.58%   +0.03%     
==========================================
  Files         110      110              
  Lines        5222     5208      -14     
==========================================
- Hits         5094     5082      -12     
+ Misses        128      126       -2     

Flag	Coverage Δ
DI	98.64% <100.00%> (+0.05%)	⬆️
DIT	95.57% <ø> (ø)

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