spend 2 assets with different close methods

[St333p]

This PR adds a new test that uses 2 taproot wallets to issue 2 assets on the same UTXO, spends the first one and checks that the second one is still spendable after going through a blank transition.

The second pay() (which should spend the blank allocation from the previous transfer) fails in some cases, with different errors depending on the selected close methods for the two assets:

• both tapret: success
• both opret: pay() fails with Composition(Stock("the spent UTXOs contain too many seals which can't fit the state transition input limit."))
• send opret, blank tapret: pay() fails with Composition(Stock("the spent UTXOs contain too many seals which can't fit the state transition input limit."))
• send tapret, blank opret: pay() fails with Composition(Construction(NoInputs))

[St333p]

Rebased on top of master and added the ignore flag to the failing cases as per README instructions

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 37.23%. Comparing base (67c6b65) to head (457b51b).
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #24      +/-   ##
==========================================
- Coverage   37.23%   37.23%   -0.01%     
==========================================
  Files         279      279              
  Lines       42806    42806              
==========================================
- Hits        15938    15937       -1     
- Misses      26868    26869       +1     

Flag	Coverage Δ
rust	37.23% <ø> (-0.01%)	⬇️

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[dr-orlovsky]

Two issues revealed by this test:

• Blank transition fails to construct when multiple close methods are involved rgb-std#284
• Diverging opret/tapret assignments are skipped for an outpoint rgb-std#290