feat(gnovm): align Gno constant handling with Go specifications

[omarsy]

Related Issues:
Closes #2628

This PR aims to align Gno's constant handling with the Go specification regarding constant expressions (see Go Specification on Constants).

1. Primitive Type Requirement

   • Should Work:

     const t = 1

   • Should Return an Error:

     const t = []string{"1"}

     Error:

     (const (slice[("1" string)] []string)) (value of type []string) is not constant
     

2. Function Calls Disallowed
   Only built-in functions should be allowed.

   • Should Work:

     const t = len("s")

   • Should Return an Error:

     func v() string {
         return ""
     }
     const t = v()

     Error:

     v<VPBlock(3,0)>() (value of type string) is not constant
     

3. Constant Operands Requirement
   Constant expressions may contain only constant operands and are evaluated at compile time.

   • Should Work:

     const t = 1
     const v = t

   • Should Raise an Error:

     t := 1
     const v = t

     Error:

     t (variable of type int) is not constant
     

4. Type Assertion Forbidden

   • This code:

     var i interface{} = 1
     const t, ok = i.(int)

   • Should Raise This Error:

     i.(int) (comma, ok expression of type int) is not constant
     

5. Index Expression Forbidden

   • This code:

     var i = []string{}
     const t, ok = i[0]

   • Should Return This Error:

     i[0] (variable of type string) is not constant
     

Contributors' checklist...

• 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
• No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided any useful hints for running manual tests
• Added new benchmarks to generated graphs, if any. More info here.

[codecov]

Codecov Report

Attention: Patch coverage is 61.01695% with 46 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
gnovm/pkg/gnolang/type_check.go	60.68%	37 Missing and 9 partials ⚠️

📢 Thoughts on this report? Let us know!

[jefft0]

@omarsy , can you fix the lint-pr-title CI check?

[ltzmaxwell]

LGTM, approve this. @omarsy thank you for fixing this.

[ltzmaxwell]

cc: @thehowl to finalize this.

[thehowl]

but the rest is good; some better documentation is appreciated but you can send it in another PR ;)