[Bug testsuite/81920] Improve timing-sensitive libgomp.oacc testcases

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81920

--- Comment #2 from Tom de Vries <vries at gcc dot gnu.org> ---
Created attachment 42027
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42027&action=edit
Updated patch

prints lines to be matched into a separate file, allowing using scan-file. When
timings are failing, show this in libgomp.sum:
...
FAIL: libgomp.oacc-c/../libgomp.oacc-c-c++-common/lib-81.c
-DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0  -O0   scan-file actual time 3 <
0.11: ok
FAIL: libgomp.oacc-c/../libgomp.oacc-c-c++-common/lib-81.c
-DACC_DEVICE_TYPE_nvidia=1 -DACC_MEM_SHARED=0  -O2   scan-file actual time 3 <
0.11: ok
...