Incorrect coverage indication in Lua

[DavidKorczynski]

The following function https://storage.googleapis.com/oss-fuzz-coverage/lua/reports/20230827/linux/src/testdir/build/lua-master/source/lstrlib.c.html#L942 is set as uncovered in the project functions overview: https://storage.googleapis.com/oss-fuzz-introspector/lua/inspector-report/20230827/fuzz_report.html#Project-functions-overview

[DavidKorczynski]

fyi @ligurio