ci: drop dash test targets from AsAN+UBSan build until spv-embedded lands (#62)

The .github/workflows/build.yml AsAN+UBSan build step references four
dash-specific test targets (test_dash_credit_pool, test_dash_subsidy,
test_dash_battletest_regressions, test_dash_pay_attribution) that do
not yet exist on master. They live on the dash-spv-embedded branch
(PR #43, 226-commit rebase in flight) where they were authored in
commit 43ef108 Dash: unit tests for CreditPool + subsidy formulas.

Result: every push to master fails the AsAN+UBSan job with
  gmake: *** No rule to make target test_dash_credit_pool. Stop.

Regular Linux x86_64 build and the Coin matrix workflow do not list
these targets and pass cleanly, so this is purely an AsAN-job-only
workflow-master mismatch, not a code regression.

Fix is tactical: remove the four target names so AsAN matches the
regular Linux job. When dash-spv-embedded merges, the dash credit-pool
PR can re-add them in the same PR that lands the tests, keeping the
AsAN+UBSan job sanitizer-instrumented against the new code from
day-one.

Author: frstrtr

.github/workflows/build.yml

@@ -191,8 +191,6 @@ jobs:
                     test_mweb_builder \
                     test_address_resolution test_compute_share_target \
                     test_utxo \
-                    test_dash_credit_pool test_dash_subsidy test_dash_battletest_regressions \
-                    test_dash_pay_attribution \
                     test_coin_broadcaster test_multiaddress_pplns test_pplns_stress \
             -j$(nproc)