fix[ux]: catch extcalls in range expr and loop iterator

[tserg]

What I did

Fix #3867

How I did it

Add a check for Extcall nodes in a range call and as loop iterator.

How to verify it

See tests.

Commit message

fix: catch extcalls in range expr and loop iterator

This PR improves the error message when an external call is made
in a for loop as part of a `range` expression or as the loop iterator.

Description for the changelog

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[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.36%. Comparing base (f8d4b97) to head (2772e37).

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Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3884   +/-   ##
=======================================
  Coverage   86.36%   86.36%           
=======================================
  Files          92       92           
  Lines       14024    14026    +2     
  Branches     3081     3082    +1     
=======================================
+ Hits        12112    12114    +2     
  Misses       1484     1484           
  Partials      428      428           

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[charles-cooper]

interesting that we don't need (as much) analysis anymore. but i'm not sure this works for side effecting expressions which aren't marked with extcall (e.g. raw_call, internal calls which result in state changes, etc). i think a more robust solution is going to be to pass around a context variable with the current scope's modifiability information

[charles-cooper]

this is a dup of #3546 no?

[cyberthirst]

interface I:
    def bar() -> DynArray[uint256, 10]: nonpayable

@external
def bar(t: address):
    for i: uint256 in extcall I(t).bar():
        pass

vyper.exceptions.CodegenPanic: unhandled exception typechecker missed this, parse_ExtCall

  contract "tests/custom/test4.vy:6", function "bar", line 6:22 
       5 def bar(t: address):
  ---> 6     for i: uint256 in extcall I(t).bar():
  -----------------------------^
       7         pass


This is an unhandled internal compiler error. Please create an issue on Github to notify the developers!
https:/vyperlang/vyper/issues/new?template=bug.md