rpcrt4/tests: Don't load GetUserNameEx dynamically.

[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
https://testbot.winehq.org/JobDetails.pl?Key=25430

Your paranoid android.


=== w864 (32 bit rpc) ===
rpc.c:815: Test failed: GUID does not appear to contain a MAC address: {9d7329b2-6dfd-11e6-be78-e71666c2e04a}

=== w864 (64 bit rpc) ===
rpc.c:815: Test failed: GUID does not appear to contain a MAC address: {cfff88a2-6dfd-11e6-be78-e71666c2e04a}

=== w8 (32 bit server) ===
server.c:1010: Test failed: get_ranged_enum() returned 2000814083 instead of RE3

=== w864 (32 bit server) ===
server.c:1010: Test failed: get_ranged_enum() returned 2009071619 instead of RE3
server.c:1010: Test failed: get_ranged_enum() returned 2009071619 instead of RE3
server.c:1010: Test failed: get_ranged_enum() returned 2009071619 instead of RE3

=== w864 (64 bit server) ===
server.c:1010: Test failed: get_ranged_enum() returned 4390915 instead of RE3
server.c:1010: Test failed: get_ranged_enum() returned 117440515 instead of RE3
server.c:1010: Test failed: get_ranged_enum() returned 4390915 instead of RE3

=== w1064 (64 bit server) ===
server.c:1010: Test failed: get_ranged_enum() returned 6356995 instead of RE3
server.c:1010: Test failed: get_ranged_enum() returned 6029315 instead of RE3