fix: fix builtin 'modpath()' returns empty

[zong-zhe]

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

• N
• Y

fix #1799

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

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

[coveralls]

Pull Request Test Coverage Report for Build 12764387554

Details

• 26 of 27 (96.3%) changed or added relevant lines in 2 files are covered.
• 2 unchanged lines in 2 files lost coverage.
• Overall coverage increased (+0.03%) to 70.58%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
kclvm/parser/src/entry.rs	5	6	83.33%

Files with Coverage Reduction	New Missed Lines	%
kclvm/tools/src/LSP/src/request.rs	1	66.14%
kclvm/sema/src/advanced_resolver/node.rs	1	84.99%

Totals
Change from base Build 12759901294:	0.03%
Covered Lines:	52875
Relevant Lines:	74915

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💛 - Coveralls