test/ruby/test_process.rb: simplify testing spawn with long strings

test_aspawn_too_long_path just wants to verify that passing a very long
string to spawn does not cause a crash. Use an input string that is long
enough for this purpose and does not ends up with spawning too many
processes.

This change makes this test run much faster on systems where /bin/sh is
bash, which retries fork() several times with long delays before giving
up.

(cherry picked from commit fa8df43)

Author: rhenium

test/ruby/test_process.rb

@@ -1802,46 +1802,29 @@ def test_fallback_to_sh
 
   def test_spawn_too_long_path
     bug4314 = '[ruby-core:34842]'
-    assert_fail_too_long_path(%w"echo", bug4314)
+    assert_fail_too_long_path(false, bug4314)
   end
 
   def test_aspawn_too_long_path
-    bug4315 = '[ruby-core:34833] #7904 [ruby-core:52628] #11613'
-    assert_fail_too_long_path(%w"echo |", bug4315)
+    bug4315 = '[ruby-core:34833]'
+    assert_fail_too_long_path(true, bug4315)
   end
 
-  def assert_fail_too_long_path((cmd, sep), mesg)
-    sep ||= ""
-    min = 1_000 / (cmd.size + sep.size)
-    cmds = Array.new(min, cmd)
+  def assert_fail_too_long_path(use_shell, mesg)
+    cmd = "a" * 10_000_000
+    cmd.prepend("echo|") if use_shell
     exs = [Errno::ENOENT]
     exs << Errno::EINVAL if windows?
     exs << Errno::E2BIG if defined?(Errno::E2BIG)
     opts = {[STDOUT, STDERR]=>File::NULL}
-    if defined?(Process::RLIMIT_NPROC)
-      opts[:rlimit_nproc] = /openbsd/i =~ RUBY_PLATFORM ? 64 : 128
-    end
-    EnvUtil.suppress_warning do
-      assert_raise(*exs, mesg) do
-        begin
-          loop do
-            Process.spawn(cmds.join(sep), opts)
-            min = [cmds.size, min].max
-            begin
-              cmds *= 100
-            rescue ArgumentError
-              raise NoMemoryError
-            end
-          end
-        rescue NoMemoryError
-          size = cmds.size
-          raise if min >= size - 1
-          min = [min, size /= 2].max
-          cmds[size..-1] = []
-          raise if size < 250
-          retry
-        end
+    begin
+      EnvUtil.suppress_warning do
+        Process.spawn(cmd, opts)
       end
+    rescue => e
+      assert_include(exs, e.class, mesg)
+    else
+      omit "system supports very long command line; skipping"
     end
   end