Remove unused expected output file

[jafingerhut]

No description provided.

[jafingerhut]

Here are all files in the p4c repo containing psa-example-dpdk-varbit in their name before this PR. All of them except the file being removed by this PR end with a -bmv2 suffix, so the file removed by this PR, without the -bmv2 suffix, appears to be unused.

$ find . | grep psa-example-dpdk-varbit
./testdata/p4_16_samples_outputs/psa-example-dpdk-varbit-bmv2.p4.p4info.txt
./testdata/p4_16_samples_outputs/psa-example-dpdk-varbit-bmv2-frontend.p4
./testdata/p4_16_samples_outputs/psa-example-dpdk-varbit-bmv2.p4-stderr
./testdata/p4_16_samples_outputs/psa-example-dpdk-varbit-bmv2.p4
./testdata/p4_16_samples_outputs/psa-example-dpdk-varbit-bmv2.p4.entries.txt
./testdata/p4_16_samples_outputs/psa-example-dpdk-varbit-bmv2-first.p4
./testdata/p4_16_samples_outputs/psa-example-dpdk-varbit-bmv2-midend.p4
./testdata/p4_16_samples_outputs/psa-example-dpdk-varbit.p4-stderr
./testdata/p4_16_samples_outputs/psa-example-dpdk-varbit-bmv2.p4.spec
./testdata/p4_16_samples_outputs/psa-example-dpdk-varbit-bmv2.p4-error
./testdata/p4_16_samples_outputs/psa-example-dpdk-varbit-bmv2.p4.bfrt.json
./testdata/p4_16_samples/psa-example-dpdk-varbit-bmv2.stf
./testdata/p4_16_samples/psa-example-dpdk-varbit-bmv2.p4