[llvm] [lit] Ignore src permissions when copying lit_test_times (PR #121377)

[Angus Lees via llvm-commits]

anguslees wrote:

> but I'm now confused by why https://github.com/llvm/llvm-project/commit/1dbcb79498d0db465234c68adf52b88e7f87a832 isn't sufficient?

This is not about bazel.  If `%{inputs}/reorder/lit_test_times` is 0444 for some reason, then we need this fix.

_It just so happens_ that in my bazel build environment, input files are presented as 0444.  This is not the usual/default bazel setup, and it's unlikely that other bazel users will experience this same issue.  But again: this is not about bazel.  I can contrive other non-bazel scenarios where input source is read-only, if that will help.

https://github.com/llvm/llvm-project/pull/121377