REPL: Adjust existing tests for verification call insertion
Adapt all existing tests to work with the new insertion mechanism:
Instead of testing `modules_to_be_loaded()` which scanned the AST,
the tests now verify that `insert_package_verification_calls()` correctly
inserts verification calls into the AST for the same test cases:
- Basic using/import statements
- Multiple packages in one statement
- Submodule imports (using Foo.bar, Foo.baz)
- Conditional using statements (if false using Foo end)
- Nested conditionals
- Import with 'as' syntax
- Exclusions: Base, Main, Core, local modules
- Quoted expressions (should not insert verification)
- Dynamic eval cases
- Local import syntax variations
Plus one new test for batching: consecutive using statements should
result in a single verification call with all packages.
All original test coverage is preserved, just adapted to the new mechanism.
