feat: top level variable back reference for the evaluator

[Peefy]

1. Does this PR affect any open issues?(Y/N) and add issue references (e.g. "fix #123", "re #123".):

• N
• Y

Closes #247
Closes kcl-lang/kpm#241
Closes #1176

feat: top level variable back reference

2. What is the scope of this PR (e.g. component or file name):

• kclvm/evaluator/src/context.rs
• kclvm/evaluator/src/func.rs
• kclvm/evaluator/src/lazy.rs
• kclvm/evaluator/src/lib.rs
• kclvm/evaluator/src/module.rs
• kclvm/evaluator/src/node.rs
• kclvm/evaluator/src/proxy.rs
• kclvm/evaluator/src/schema.rs
• kclvm/evaluator/src/scope.rs
• kclvm/evaluator/src/ty.rs
• kclvm/runner/benches/bench_runner.rs
• kclvm/runner/src/assembler.rs
• kclvm/runner/src/lib.rs
• kclvm/runner/src/runner.rs
• kclvm/runtime/src/value/val_func.rs

3. Provide a description of the PR(e.g. more details, effects, motivations or doc link):

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Other

4. Are there any breaking changes?(Y/N) and describe the breaking changes(e.g. more details, motivations or doc link):

• N
• Y

5. Are there test cases for these changes?(Y/N) select and add more details, references or doc links:

• Unit test
• Integration test
• Benchmark (add benchmark stats below)
• Manual test (add detailed scripts or steps below)
• Other

• kclvm/evaluator/src/snapshots/kclvm_evaluator__tests__lazy_scope_0.snap
• kclvm/evaluator/src/snapshots/kclvm_evaluator__tests__lazy_scope_1.snap
• kclvm/evaluator/src/snapshots/kclvm_evaluator__tests__lazy_scope_2.snap
• kclvm/runner/src/tests.rs

[coveralls]

Pull Request Test Coverage Report for Build 8627481438

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 246 of 271 (90.77%) changed or added relevant lines in 17 files are covered.
• 2942 unchanged lines in 14 files lost coverage.
• Overall coverage decreased (-1.4%) to 71.203%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
kclvm/evaluator/src/func.rs	0	1	0.0%
kclvm/evaluator/src/proxy.rs	0	1	0.0%
kclvm/evaluator/src/ty.rs	10	11	90.91%
kclvm/runtime/src/value/val_func.rs	3	4	75.0%
kclvm/runner/src/lib.rs	7	9	77.78%
kclvm/evaluator/src/schema.rs	14	17	82.35%
kclvm/evaluator/src/lazy.rs	73	77	94.81%
kclvm/evaluator/src/scope.rs	50	55	90.91%
kclvm/evaluator/src/node.rs	22	29	75.86%

Files with Coverage Reduction	New Missed Lines	%
kclvm/runtime/src/value/val_func.rs	1	88.89%
kclvm/evaluator/src/scope.rs	1	89.89%
kclvm/sema/src/ty/unify.rs	1	97.81%
kclvm/ast/src/ast.rs	1	83.49%
kclvm/compiler/src/value/schema.rs	10	0.0%
kclvm/runner/src/runner.rs	13	89.43%
kclvm/compiler/src/codegen/llvm/backtrack.rs	16	0.0%
kclvm/config/src/cache.rs	17	89.55%
kclvm/compiler/src/codegen/llvm/utils.rs	20	63.64%
kclvm/compiler/src/codegen/llvm/module.rs	27	66.67%

Totals
Change from base Build 8617183262:	-1.4%
Covered Lines:	46929
Relevant Lines:	65909

---

💛 - Coveralls