fix(sourcemap): keep line-start mappings when chaining input maps

[kdy1]

Description:

Related issue:

• Closes SWC generates incorrect source maps when typescript inputSourceMap is provided #10504

[changeset-bot]

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Latest commit: b864462

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[github-actions]

Binary Sizes

File	Size
swc.linux-x64-gnu.node	28M (28588488 bytes)

Commit: 1b992d6

[codspeed-hq]

Merging this PR will not alter performance

✅ 184 untouched benchmarks

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_{Comparing kdy1/fix-issue-10504-sourcemap (b864462) with main (b24b8e0)}