Remove redundant ci jobs

[mcbarton]

@vgvassilev The non cppyy or xeus-clang-repl jobs for osx and Ubuntu are redundant. They don't do anything that the cppyy and xeus-clang-repl jobs don't (there was one small valgrind dependence for Ubuntu but this has been removed in this PR). I have removed them so that free Github runner minutes are not wasted, and so we can run through the osx jobs quicker (the maximum number of concurrent osx jobs allowed is 5, so we are currently have to wait longer than necessary for osx PR jobs to run).

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (eb2f4ef) 78.53% compared to head (cd91c8d) 78.63%.

Additional details and impacted files

[](https://app.codecov.io/gh/compiler-research/CppInterOp/pull/197?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=compiler-research) ```diff @@ Coverage Diff @@ ## main #197 +/- ## ========================================== + Coverage 78.53% 78.63% +0.09% ========================================== Files 8 8 Lines 3056 3056 ========================================== + Hits 2400 2403 +3 + Misses 656 653 -3 ``` [see 2 files with indirect coverage changes](https://app.codecov.io/gh/compiler-research/CppInterOp/pull/197/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=compiler-research) [see 2 files with indirect coverage changes](https://app.codecov.io/gh/compiler-research/CppInterOp/pull/197/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=compiler-research)

[mcbarton]

@alexander-penev can you review this PR for me?