[v0.9.0-alpha.1] feat: top level variable back reference

[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
Closes #1253

feat: top level variable back reference

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

• kclvm/compiler/src/codegen/llvm/context.rs
• kclvm/compiler/src/codegen/llvm/emit.rs
• kclvm/compiler/src/codegen/llvm/module.rs
• kclvm/runtime/src/_kcl_run.rs
• kclvm/runtime/src/eval/**

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

• test/grammar/schema/irrelevant_order/simple_6/main.k
• test/grammar/schema/irrelevant_order/simple_7/main.k
• test/grammar/schema/irrelevant_order/simple_8/main.k

[coveralls]

Pull Request Test Coverage Report for Build 9000600409

Details

• 62 of 88 (70.45%) changed or added relevant lines in 7 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.3%) to 71.406%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
kclvm/runtime/src/_kclvm_addr.rs	0	1	0.0%
kclvm/runtime/src/context/api.rs	0	1	0.0%
kclvm/compiler/src/codegen/llvm/node.rs	7	11	63.64%
kclvm/compiler/src/codegen/llvm/context.rs	49	59	83.05%
kclvm/runtime/src/_kcl_run.rs	0	10	0.0%

Totals
Change from base Build 9000204859:	0.3%
Covered Lines:	53271
Relevant Lines:	74603

---

💛 - Coveralls