Remove openblas set_num_threads in julia __init__ (#42442)

* Remove openblas_set_num_threads in julia __init__

* Remove test no longer needed.

Author: ViralBShah

base/Base.jl

@@ -462,18 +462,9 @@ end
 if is_primary_base_module
 function __init__()
     # try to ensuremake sure OpenBLAS does not set CPU affinity (#1070, #9639)
-    if !haskey(ENV, "OPENBLAS_MAIN_FREE") && !haskey(ENV, "GOTOBLAS_MAIN_FREE")
+    if !haskey(ENV, "OPENBLAS_MAIN_FREE")
         ENV["OPENBLAS_MAIN_FREE"] = "1"
     end
-    # And try to prevent openblas from starting too many threads, unless/until specifically requested
-    if !haskey(ENV, "OPENBLAS_NUM_THREADS") && !haskey(ENV, "OMP_NUM_THREADS")
-        cpu_threads = Sys.CPU_THREADS::Int
-        if cpu_threads > 8 # always at most 8
-            ENV["OPENBLAS_NUM_THREADS"] = "8"
-        elseif haskey(ENV, "JULIA_CPU_THREADS") # or exactly as specified
-            ENV["OPENBLAS_NUM_THREADS"] = cpu_threads
-        end # otherwise, trust that openblas will pick CPU_THREADS anyways, without any intervention
-    end
     # for the few uses of Libc.rand in Base:
     Libc.srand()
     # Base library init

stdlib/Distributed/test/distributed_exec.jl

@@ -1031,7 +1031,6 @@ function test_add_procs_threaded_blas()
         @warn "Skipping blas num threads tests due to unsupported blas version"
         return
     end
-    @test master_blas_thread_count <= 8 # check that Base set the environment variable in __init__ before LinearAlgebra dlopen'd it
 
     # Test with default enable_threaded_blas false
     processes_added = addprocs_with_testenv(2)