feat: PrevRealm ignores user realms

[tbruyelle]

Fix #1664

As commented in the IsRealm() method, a better format of user realms should emerge in the form of gno.land/u/user_address, which would remove the confusion between standard realms and the realm forged under the MsgRun transaction.

BREAKING CHANGE: std.PrevRealm is not returning the user realm any more when invoked under a transaction broadcasted by MsgRun.

To run the txtar test:

$ go test ./gno.land/cmd/gnoland/ -v -run TestTestdata/prevrealm

Contributors' checklist...

• [x] Added new tests, or not needed, or not feasible
• [ ] Provided an example (e.g. screenshot) to aid review or the PR is self-explanatory
• [ ] Updated the official documentation or not needed
• [x] No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• [x] Added references to related issues and PRs
• [x] Provided any useful hints for running manual tests
• [ ] Added new benchmarks to generated graphs, if any. More info here.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 75.00000% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 49.01%. Comparing base (e1586a5) to head (89f6938).

Files	Patch %	Lines
gno.land/pkg/sdk/vm/keeper.go	0.00%	0 Missing and 1 partial :warning:

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1719   +/-   ##
=======================================
  Coverage   49.01%   49.01%           
=======================================
  Files         576      576           
  Lines       77604    77605    +1     
=======================================
+ Hits        38035    38036    +1     
- Misses      36486    36487    +1     
+ Partials     3083     3082    -1     

Flag	Coverage Δ
gno.land	61.69% <0.00%> (ø)
gnovm	41.94% <100.00%> (-0.03%)	:arrow_down:

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[leohhhn]

@tbruyelle If I understand correctly, this only modifies the PrevRealm in case of MsgRun? If so, I changed the name of the PR to make it more clear

[tbruyelle]

@tbruyelle If I understand correctly, this only modifies the PrevRealm in case of MsgRun? If so, I changed the name of the PR to make it more clear

Yes, this is exactly that, thanks for the clarification.