[test_server] Use simpler tc name in unicode test to make it work on windows

A test case in test_server_unicode_SUITE contained characters that
were not allowed in filenames on windows - e.g. \. The test case name
will be used as filename for the HTML log for the test, so this failed
on windows. This is now corrected.
[test_server] Fix encoding of HTML file references to work on windows

The URI encoding when in unicode  file name mode did not preserve @, :
and  /, and  thus  some links  were  did not  work  on windows  (think
c:/). This has been corrected.
[reltool] Increase timetrap timeout for reltool_server_SUTIE to 10 minutes

The timeout of 5 minutes sometimes expired for test case
use_selected_vsn on some platforms.
[test_server] Clean up unused code in test_server_SUITE
[common_test] Extend timers for slave nodes in ct_cover_SUITE

Also, rename some nodes to avoid node name clash between test cases,
and ensure proper cleanup of nodes.
[jinterface] Make tests handle space in path on windows

Add quotes around classpath on windows.
[observer] Fix non tail-recusive loop when measuring scheduler utilization
[observer] Improve measurement of CPU utilization in etop

Now using scheduler_wall_time instead of runtime/wall_clock to get cpu
utilization. The old version could give CPU utilization far beyond 100%.

Also, a bug which sometimes gave a badarith when calculating the CPU
utilization is corrected.
[observer] Accept current function for a process to be 'undefined' on hipe
[observer] Kill slave node between tests in etop_SUITE

To avoid that the second test case fails (due to duplicate name) if
the first fails - always kill the slave node after each test case.
[observer] Extend timer to allow trace msgs to arrive over tcp/ip

Some tests fail (mostly on windows) every now and then with too few
trace messages in log. Extending the timer from 200 to 500 ms to see
if this is the reason.

Plus removing a compiler warning in ttb_SUITE.
[jinterface] Kill process between tests to avoid consequential error

In some cases when a test case fails, the erl_link_server process
(which is spawned by many test cases in jinterface_SUITE) does not
terminate. This causes the next test case to fail with a badarg as it
tries to register a new process with the same name. To avoid this,
erl_link_server, if it exists, is now killed in end_per_testcase.

Also, some compiler warnings are removed from jitu.erl.
PER/UPER: Correct decoding of ENUMERATEDs with a single value

An ENUMERATED with as single value is not encoded. The decoder
incorrectly assumed that it was encoded in one bit.
PER: Ensure that the complete encoding is at least one byte

If the encoding is empty (i.e. if a top-level type is single-valued
and therefore not encoding), the result should be a single zero
byte.
Add ct_slave:start(Node, Opts) to start a node on the local host

This is convenient when starting nodes locally since there's otherwise
no trivial way to specify the local hostname.
Minor edoc fix

edoc inserted a type spec into the signature ("Options :: Opts") when
@spec and code used different variable names.
Simplify doc of error return

As {error, Reason, NodeName} together with a Reason production.
Returning '/' when given as parameter to get_testdir
Merge branch 'bjorn/asn1/per-decode/OTP-10916' into maint-r16

* bjorn/asn1/per-decode/OTP-10916:
  PER: Ensure that the complete encoding is at least one byte
  PER/UPER: Correct decoding of ENUMERATEDs with a single value
Prepare release