Implement dead code elimination

[heshanpadmasiri]

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Purpose

Merge the optimization in #43013 with master

Fixes #43111

Approach

For a detailed explanation please checkout the original PR (#43013)

Samples

Provide high-level details about the samples related to this feature.

Remarks

List any other known issues, related PRs, TODO items, or any other notes related to the PR.

Check List

• [x] Read the Contributing Guide
• [ ] Updated Change Log
• [ ] Checked Tooling Support (#<Issue Number>)
• [ ] Added necessary tests
  • [ ] Unit Tests
  • [ ] Spec Conformance Tests
  • [ ] Integration Tests
  • [ ] Ballerina By Example Tests
• [ ] Increased Test Coverage
• [ ] Added necessary documentation
  • [ ] API documentation
  • [ ] Module documentation in Module.md files
  • [ ] Ballerina By Examples