Remove Rust version divergence when Rust 1.100 hits stable

[nicolas-guichard]

grcov/src/llvm_tools.rs

Line 461 in f39a787

// Starting with rustc nightly-2026-09-07, lines 4 and 6 are not counted as code lines anymore.

added two possible cases for that test output depending on the Rust version. Once Rust 1.100 (currently in Nightly) hits stable we can remove the old expectation.

Originally posted by @marco-c in #1519 (comment)