Some conformance tests a bit slow under Valgrind

[Dan Kegel]

Under Valgrind, on my nice fast e7200 system,
the entire suite of tests takes about three hours to run.

The slowest ten percent of the tests take over a third of the runtime.

riched20's editor.c in particular spends way too long
(I think) on test_EM_AUTOURLDETECT.

The min, median, and max times to run a test
are 10 seconds, 19 seconds, and 15 minutes.

15:44.05elapsed riched20.dll editor.c
6:35.94elapsed d3d9.dll visual.c
5:45.43elapsed shell32.dll shlexec.c
3:28.98elapsed kernel32.dll process.c
2:49.85elapsed winmm.dll wave.c
2:32.18elapsed kernel32.dll debugger.c
2:14.41elapsed gdiplus.dll font.c
1:44.54elapsed dsound.dll capture.c
1:29.51elapsed mshtml.dll dom.c
...
0:18.84elapsed shlwapi.dll path.c
0:18.83elapsed rpcrt4.dll cstub.c
...
0:09.92elapsed ntdll.dll path.c
0:09.92elapsed msvcrt.dll data.c

I guess I'm not complaining, but perhaps we could tone
down test_EM_AUTOURLDETECT a bit.