tests: fix build on old 32-bit platforms
    
    gcc 4.1.2 (hello RHEL 5) on 32-bit platforms complains:
    
    vircgrouptest.c: In function 'testCgroupGetPercpuStats':
    vircgrouptest.c:627: warning: integer constant is too large for 'long' type
    vircgrouptest.c:628: warning: this decimal constant is unsigned only in ISO C90
    vircgrouptest.c:634: warning: integer constant is too large for 'long' type
    vircgrouptest.c:635: warning: this decimal constant is unsigned only in ISO C90
    vircgrouptest.c:636: warning: this decimal constant is unsigned only in ISO C90
    vircgrouptest.c:644: warning: integer constant is too large for 'long' type
    
    * tests/vircgrouptest.c (testCgroupGetPercpuStats): Use ULL suffix.
    
    Signed-off-by: Eric Blake <eblake@redhat.com>