Add fromBigEndianBytes conversion function to Number types

[darkdrag00nv2]

Closes #2448
Work towards onflow/developer-grants#179

Description

Added fromBigEndianBytes to all the Number types - Int*, UInt*, Fix*, Word*.

We return Nil in case of invalid input such as overflow. Note that we also return Nil if the size of the byte array is greater than the size needed for the target type. E.g. [0, 0] does not lead to overflow for UInt8 but we return Nil since we expect the byte array size to only be 1.

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• Targeted PR against master branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• Code follows the standards mentioned here
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels

[codecov]

Codecov Report

Merging #2496 (57f4b9c) into master (043b805) will increase coverage by 0.04%.
The diff coverage is 92.52%.

@@            Coverage Diff             @@
##           master    #2496      +/-   ##
==========================================
+ Coverage   78.35%   78.39%   +0.04%     
==========================================
  Files         327      327              
  Lines       73044    73262     +218     
==========================================
+ Hits        57235    57436     +201     
- Misses      13710    13720      +10     
- Partials     2099     2106       +7     

Flag	Coverage Δ
unittests	78.39% <92.52%> (+0.04%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
runtime/interpreter/interpreter.go	89.89% <90.24%> (+0.01%)	⬆️
runtime/interpreter/big.go	89.47% <100.00%> (+5.68%)	⬆️
runtime/sema/type.go	89.52% <100.00%> (+0.07%)	⬆️

... and 1 file with indirect coverage changes

[turbolent]

Just realized that #1917 fixed the behaviour for toBigEndianBytes on the Stable Cadence feature branch (feature/stable-cadence).
Maybe we should target this PR against Stable Cadence too @onflow/cadence ?

[turbolent]

Nice!

[darkdrag00nv2]

Maybe we should target this PR against Stable Cadence too @onflow/cadence ?

@turbolent sure, I can switch the branch to stable cadence if needed. In future, when the stable cadence branch is fully merged into master, these changes will also come in. Do let me know.

[SupunS]

Just realized that #1917 fixed the behaviour for toBigEndianBytes on the Stable Cadence feature branch (feature/stable-cadence).
Maybe we should target this PR against Stable Cadence too ?

Sorry, I missed this. Does the new API fromBigEndianBytes work with fixed-size inputs or variable-sized inputs (both)?
If it seamlessly works for both, then I see no harm in merging this to master.

Otherwise, If we'll have to do any adjustments, then merging to Stable Cadence directly sounds like a good idea. It would save us the trouble of having to maintain two versions of this / update to match the Stable cadence later on (which could fall through the cracks). But like I said, if this is not the case, then I'm OK with merging to master.

[darkdrag00nv2]

Does the new API fromBigEndianBytes work with fixed-size inputs or variable-sized inputs (both)?
If it seamlessly works for both, then I see no harm in merging this to master.

@SupunS Yes, it works for both the cases. For variable-sized inputs, we add the necessary padding.

[turbolent]

Nice work!

[turbolent]

@onflow/cadence could you please have a look?