test-local-addresses: drop racy check

test-local-addresses: drop racy check

The test would fail when addresses were being removed in parallel. In general,
the check is only valid when the machine configuration is static, which in
general isn't true.

CentOS CI (Arch Linux) fails in TEST-02-UNITTESTS test-local-addresses:

10:38:05 (gdb) #0  0x00007f86260a164c in ?? () from /usr/lib/libc.so.6
10:38:05 No symbol table info available.
10:38:05 #1  0x00007f8626051958 in raise () from /usr/lib/libc.so.6
10:38:05 No symbol table info available.
10:38:05 #2  0x00007f862603b53d in abort () from /usr/lib/libc.so.6
10:38:05 No symbol table info available.
10:38:05 #3  0x00007f862639a755 in log_assert_failed (
10:38:05     text=text@entry=0x56180e56c03b "n == n_ipv4 + n_ipv6",
10:38:05     file=file@entry=0x56180e56c0d1 "src/test/test-local-addresses.c",
10:38:05     line=line@entry=45,
10:38:05     func=func@entry=0x56180e56c360 <__PRETTY_FUNCTION__.6> "test_local_addresses") at ../build/src/basic/log.c:853
10:38:05 No locals.
10:38:05 #4  0x000056180e56b77e in test_local_addresses ()
10:38:05     at ../build/src/test/test-local-addresses.c:45
10:38:05         a = 0x0
10:38:05         n = 234
10:38:05         n_ipv4 = 236
10:38:05         n_ipv6 = 7
10:38:05         __PRETTY_FUNCTION__ = "test_local_addresses"
10:38:05         __func__ = "test_local_addresses"
10:38:05 #5  0x000056180e56ba67 in run_test_table () at ../build/src/shared/tests.h:106
10:38:05         r = 0
10:38:05         t = 0x56180e56e010 <__unique_prefix_static_test_table_entry10>
10:38:05         __PRETTY_FUNCTION__ = <optimized out>
10:38:05         __func__ = "run_test_table"
10:38:05 #6  0x000056180e56bb2f in main (argc=1, argv=0x7ffc3a814808)
10:38:05     at ../build/src/test/test-local-addresses.c:81
10:38:05         _intro = 0x0
10:38:05         _outro = 0x0
10:38:05         _r = 0
10:38:05         _q = 0
10:38:05 (gdb)

The logs show that there's a huge number of private addresses, probably from
some other test running in parallel.