[PATCH] advapi32/tests: Fix an uninitialized variable check in test_performance_keys().

[Francois Gouget]

On Mon, 16 Aug 2021, Marvin wrote:
[...]
> === w10pro64_zh_CN (64 bit report) ===
> 
> advapi32:
> registry.c:568: Test failed: data_count set to 9 instead of 7
> registry.c:572: Test failed: data set to 'xxxxxxxxx' instead of 'foobar' or 'xxxxxxx'

This is one of the other random failures we get with advapi32:registry. 
The annoying part is that while here we get 9, other times it was either 
13 or 10 and whenever the value changes it looks like a new failure to 
the TestBot.

There are also several lines where it can happen so it combines to 
produce several different failure modes.

So if someone wants to look into it that will certainly avoid a bumch of 
false positives.

https://test.winehq.org/data/patterns.html#advapi32:registry

-- 
Francois Gouget <fgouget at codeweavers.com>