[llvm] [test-suite] Document the LLVM test-suite benchmark apps (PR #105843)

[Sjoerd Meijer via llvm-commits]

sjoerdmeijer wrote:

> Seems like a good idea to me. Is it worth adding a column to state whether it's suitable for performance measurements? I guess my broader question would be whether that information is still encoded correctly in CMake too...

Thanks, good point.

I have checked that all apps are suitable for perf measurements. I.e., non of the top-level apps/directories are excluded, and only a few apps (benchmark suites) have sub-directories that are excluded when TEST_SUITE_BENCHMARKING_ONLY is not set, for example this is the pattern:

     ...
    add_subdirectory(17-bintr)
    add_subdirectory(18-imp)
    if(NOT TEST_SUITE_BENCHMARKING_ONLY)
        add_subdirectory(15-trie)
    endif()

I have removed these benchmark from the "remark" column if it was included and spelled out to be part of the benchmark suite, and added a sentence that should clarify that all apps are suitable for perf measurements.

https://github.com/llvm/llvm-project/pull/105843