[PATCH v4] quartz: Fix crash when pVisible is NULL.

[Marvin]

Hi,

While running your changed tests, 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:
https://testbot.winehq.org/JobDetails.pl?Key=78360

Your paranoid android.


=== w10pro64_ja (32 bit report) ===

quartz:
videorenderer.c:1078: Test failed: Wait failed.
videorenderer.c:1079: Test failed: Got hr 0x103.
videorenderer.c:1088: Test failed: Thread should block in Receive().

=== w10pro64_zh_CN (32 bit report) ===

quartz:
videorenderer.c:1098: Test failed: Got hr 0x80004005.

=== w10pro64 (64 bit report) ===

quartz:
videorenderer.c:1088: Test failed: Thread should block in Receive().

=== w10pro64_2scr (64 bit report) ===

quartz:
videorenderer.c:1098: Test failed: Got hr 0x80004005.

=== w10pro64_he (64 bit report) ===

quartz:
videorenderer.c:1098: Test failed: Got hr 0x80004005.

=== w10pro64_ja (64 bit report) ===

quartz:
videorenderer.c:1098: Test failed: Got hr 0x80004005.