Restore cmdlineargs tests on non-Windows platforms (JuliaLang#55368)

Author: giordano

test/cmdlineargs.jl

@@ -339,43 +339,37 @@ let exename = `$(Base.julia_cmd()) --startup-file=no --color=no`
     @test errors_not_signals(`$exename -C invalidtarget`)
     @test errors_not_signals(`$exename --cpu-target=invalidtarget`)
 
-    if Sys.iswindows()
-        # -t, --threads
-        code = "print(Threads.threadpoolsize())"
-        cpu_threads = ccall(:jl_effective_threads, Int32, ())
-        @test string(cpu_threads) ==
-            read(`$exename --threads auto -e $code`, String) ==
-            read(`$exename --threads=auto -e $code`, String) ==
-            read(`$exename -tauto -e $code`, String) ==
-            read(`$exename -t auto -e $code`, String)
-        for nt in (nothing, "1")
-            withenv("JULIA_NUM_THREADS" => nt) do
-                @test read(`$exename --threads=2 -e $code`, String) ==
-                    read(`$exename -t 2 -e $code`, String) == "2"
-            end
-        end
-        # We want to test oversubscription, but on manycore machines, this can
-        # actually exhaust limited PID spaces
-        cpu_threads = max(2*cpu_threads, min(50, 10*cpu_threads))
-        if Sys.WORD_SIZE == 32
-            cpu_threads = min(cpu_threads, 50)
-        end
-        @test read(`$exename -t $cpu_threads -e $code`, String) == string(cpu_threads)
-        withenv("JULIA_NUM_THREADS" => string(cpu_threads)) do
-            @test read(`$exename -e $code`, String) == string(cpu_threads)
+    # -t, --threads
+    code = "print(Threads.threadpoolsize())"
+    cpu_threads = ccall(:jl_effective_threads, Int32, ())
+    @test string(cpu_threads) ==
+        read(`$exename --threads auto -e $code`, String) ==
+        read(`$exename --threads=auto -e $code`, String) ==
+        read(`$exename -tauto -e $code`, String) ==
+        read(`$exename -t auto -e $code`, String)
+    for nt in (nothing, "1")
+        withenv("JULIA_NUM_THREADS" => nt) do
+            @test read(`$exename --threads=2 -e $code`, String) ==
+                read(`$exename -t 2 -e $code`, String) == "2"
         end
-        @test errors_not_signals(`$exename -t 0`)
-        @test errors_not_signals(`$exename -t -1`)
+    end
+    # We want to test oversubscription, but on manycore machines, this can
+    # actually exhaust limited PID spaces
+    cpu_threads = max(2*cpu_threads, min(50, 10*cpu_threads))
+    if Sys.WORD_SIZE == 32
+        cpu_threads = min(cpu_threads, 50)
+    end
+    @test read(`$exename -t $cpu_threads -e $code`, String) == string(cpu_threads)
+    withenv("JULIA_NUM_THREADS" => string(cpu_threads)) do
+        @test read(`$exename -e $code`, String) == string(cpu_threads)
+    end
+    @test errors_not_signals(`$exename -t 0`)
+    @test errors_not_signals(`$exename -t -1`)
 
-        # Combining --threads and --procs: --threads does propagate
-        withenv("JULIA_NUM_THREADS" => nothing) do
-            code = "print(sum(remotecall_fetch(Threads.threadpoolsize, x) for x in procs()))"
-            @test read(`$exename -p2 -t2 -e $code`, String) == "6"
-        end
-    else
-        @test_skip "Command line tests with -t are flakey on non-Windows OS"
-        # Known issue: https://github.com/JuliaLang/julia/issues/49154
-        # These tests should be fixed and reenabled on all operating systems.
+    # Combining --threads and --procs: --threads does propagate
+    withenv("JULIA_NUM_THREADS" => nothing) do
+        code = "print(sum(remotecall_fetch(Threads.threadpoolsize, x) for x in procs()))"
+        @test read(`$exename -p2 -t2 -e $code`, String) == "6"
     end
 
     # Combining --threads and invalid -C should yield a decent error