SIGTERM should be also captured

because it will terminate the whole test process when it is
re-raised from this assertion.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52789 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/lib/envutil.rb

@@ -375,7 +375,7 @@ module Test
         assert(status.success?, "#{message} (#{status.inspect})")
       end
 
-      ABORT_SIGNALS = Signal.list.values_at(*%w"ILL ABRT BUS SEGV")
+      ABORT_SIGNALS = Signal.list.values_at(*%w"ILL ABRT BUS SEGV TERM")
 
       def assert_separately(args, file = nil, line = nil, src, ignore_stderr: nil, **opt)
         unless file and line