test: Fix build on MSVC

The MSVC compiler is very strict about variable declarations after
statements.

Move all the declarations of each block before any statement in the
same block to fix multiple instances of:

alpha-loop.c(XX) : error C2275: 'pixman_image_t' : illegal use of this
type as an expression
Merge branch 'master' of git://anongit.freedesktop.org/git/pixman