libstdc++: Reduce default test timeout to 360 seconds
The current default of 10 minutes is much longer than most tests need on
common hardware. The slow tests all now have a dg-timeout-factor
directive that gives them more time to run relative to the default. The
default can also be overridden in ~/.dejagnurc or DEJAGNU=site.exp, so
it seems unnecessary to have such a large default.
This reduces the default from 10 minutes to 6 minutes, which still seems
more than enough.
libstdc++-v3/ChangeLog:
* testsuite/lib/libstdc++.exp (libstdc++_init): Reduce
default tool_timeout to 360.