Merge branch 'selftests/bpf: Migrate test_tcpbpf_user to be a part of test_progs'

Alexander Duyck says:

====================
Move the test functionality from test_tcpbpf_user into the test_progs
framework so that it will be run any time the test_progs framework is run.
This will help to prevent future test escapes as the individual tests, such
as test_tcpbpf_user, are less likely to be run by developers and CI
tests.

As a part of moving it over the series goes through and updates the code to
make use of the existing APIs included in the test_progs framework. This is
meant to simplify and streamline the test code and avoid duplication of
effort.

v2: Dropped test_tcpbpf_user from .gitignore
    Replaced CHECK_FAIL calls with CHECK calls
    Minimized changes in patch 1 when moving the file
    Updated stg mail command line to display renames in submission
    Added shutdown logic to end of run_test function to guarantee close
    Added patch that replaces the two maps with use of global variables
v3: Left err at -1 while we are performing send/recv calls w/ data
    Drop extra labels from test_tcpbpf_user in favor of keeping err label
    Dropped redundant zero init for tcpbpf_globals result and key
    Dropped replacing of "printf(" with "fprintf(stderr, "
    Fixed error in use of ASSERT_OK_PTR which was skipping of run_test
    Replaced "{ 0 }" with "{}" in init of global in test_tcpbpf_kern.c
    Added "Acked-by" from Martin KaiFai Lau and Andrii Nakryiko
====================

Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>