[llvm] RuntimeLibcalls: Use get_host_tool_path for executables used in benchmark (PR #153955)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> Perhaps it should be guarded by ~`if (LLVM_BUILD_TOOLS)`~ `if (LLVM_INCLUDE_TOOLS)`

In the previous versions I hoped that would be implicit based on the check for the built target, that way it's not dependent on the exact set of build options if they ever change 

https://github.com/llvm/llvm-project/pull/153955