mstask/tests: Add missing call to the tested function.

[Marvin]

Hi,

While running your changed tests on Windows, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?
Full results can be found at
http://testbot.winehq.org/JobDetails.pl?Key=18417

Your paranoid android.


=== WNT4WSSP6 (32 bit task_trigger) ===
task_trigger.c:165: Test failed: Failed to setup test_task

=== W2KPROSP4 (32 bit task_trigger) ===
task_trigger.c:307: Test failed: Expected E_INVALIDARG: 0x00000000

=== WXPPROSP3 (32 bit task_trigger) ===
task_trigger.c:307: Test failed: Expected E_INVALIDARG: 0x00000000

=== W2K3R2SESP2 (32 bit task_trigger) ===
task_trigger.c:307: Test failed: Expected E_INVALIDARG: 0x00000000

=== WVISTAADM (32 bit task_trigger) ===
task_trigger.c:307: Test failed: Expected E_INVALIDARG: 0x00000000

=== W2K8SE (32 bit task_trigger) ===
task_trigger.c:307: Test failed: Expected E_INVALIDARG: 0x00000000

=== W7PRO (32 bit task_trigger) ===
task_trigger.c:307: Test failed: Expected E_INVALIDARG: 0x00000000

=== W7PROX64 (32 bit task_trigger) ===
task_trigger.c:307: Test failed: Expected E_INVALIDARG: 0x00000000

=== TEST64_W7SP1 (32 bit task_trigger) ===
task_trigger.c:307: Test failed: Expected E_INVALIDARG: 0x00000000

=== W7PROX64 (64 bit task_trigger) ===
task_trigger.c:307: Test failed: Expected E_INVALIDARG: 0x00000000

=== TEST64_W7SP1 (64 bit task_trigger) ===
task_trigger.c:307: Test failed: Expected E_INVALIDARG: 0x00000000