perf test: Fix test-record-dummy-C0 failure for supported PERF_FORMAT_LOST feature kernel

For kernel that supports PERF_FORMAT_LOST, attr->read_format has
PERF_FORMAT_LOST bit. Update expected value of
attr->read_format of test-record-dummy-C0 for this scenario.

Before:

# ./perf test 17 -vv
17: Setup struct perf_event_attr :
--- start ---
test child forked, pid 1609441
<SNIP>
running './tests/attr/test-record-dummy-C0'
'PERF_TEST_ATTR=/tmp/tmpm3s60aji ./perf record -o /tmp/tmpm3s60aji/perf.data --no-bpf-event -e dummy -C 0 kill >/dev/null 2>&1' ret '1', expected '1'
expected read_format=4, got 20
FAILED './tests/attr/test-record-dummy-C0' - match failure
test child finished with -1
---- end ----
Setup struct perf_event_attr: FAILED!

After:

# ./perf test 17 -vv
17: Setup struct perf_event_attr :
--- start ---
test child forked, pid 1609441
<SNIP>
running './tests/attr/test-record-dummy-C0'
'PERF_TEST_ATTR=/tmp/tmppa9vxcb7 ./perf record -o /tmp/tmppa9vxcb7/perf.data --no-bpf-event -e dummy -C 0 kill >/dev/null 2>&1' ret '1', expected '1'
<SNIP>
test child finished with 0
---- end ----
Setup struct perf_event_attr: Ok

Reported-and-Tested-by: Namhyung Kim <[e-mail]>
Signed-off-by: Yang Jihong <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Namhyung Kim <[e-mail]>

tools/perf/tests/attr/test-record-dummy-C0

···
 # PERF_SAMPLE_PERIOD
 # + PERF_SAMPLE_CPU added by -C 0
 sample_type=391
-read_format=4
+read_format=4|20
 disabled=0
 inherit=1
 pinned=0