kvserver: remove multiTestContext

Closes cockroachdb#8299

With all the tests converted to use TestCluster/TestServer,
we can finally remove multiTestContext and all of the dependent
code.

Release note: None
Release justification: Cleans up unused test code.

pkg/kv/kvserver/BUILD.bazel

@@ -293,12 +293,10 @@ go_test(
         "//pkg/config",
         "//pkg/config/zonepb",
         "//pkg/gossip",
-        "//pkg/gossip/resolver",
         "//pkg/keys",
         "//pkg/kv",
         "//pkg/kv/kvclient",
         "//pkg/kv/kvclient/kvcoord",
-        "//pkg/kv/kvclient/rangecache",
         "//pkg/kv/kvserver/abortspan",
         "//pkg/kv/kvserver/apply",
         "//pkg/kv/kvserver/batcheval",
@@ -374,7 +372,6 @@ go_test(
         "//pkg/util/timeutil",
         "//pkg/util/tracing",
         "//pkg/util/uuid",
-        "@com_github_cenkalti_backoff//:backoff",
         "@com_github_cockroachdb_circuitbreaker//:circuitbreaker",
         "@com_github_cockroachdb_cockroach_go//crdb",
         "@com_github_cockroachdb_datadriven//:datadriven",

pkg/kv/kvserver/client_raft_test.go

@@ -1763,36 +1763,6 @@ func TestStoreRangeUpReplicate(t *testing.T) {
 	}
 }
 
-// TestUnreplicateFirstRange verifies that multiTestContext still functions in
-// the case where the first range (which contains range metadata) is
-// unreplicated from the first store. This situation can arise occasionally in
-// tests, as can a similar situation where the first store is no longer the lease holder of
-// the first range; this verifies that those tests will not be affected.
-// TODO(lunevalex): Remove this test when removing MTC, no need to convert it
-func TestUnreplicateFirstRange(t *testing.T) {
-	defer leaktest.AfterTest(t)()
-	defer log.Scope(t).Close(t)
-
-	cfg := kvserver.TestStoreConfig(nil)
-	cfg.TestingKnobs.DisableReplicateQueue = true
-	mtc := &multiTestContext{storeConfig: &cfg}
-	defer mtc.Stop()
-	mtc.Start(t, 3)
-
-	const rangeID = roachpb.RangeID(1)
-	// Replicate the range to store 1.
-	mtc.replicateRange(rangeID, 1)
-	// Move the lease away from store 0 before removing its replica.
-	mtc.transferLease(context.Background(), rangeID, 0, 1)
-	// Unreplicate the from from store 0.
-	mtc.unreplicateRange(rangeID, 0)
-	require.NoError(t, mtc.waitForUnreplicated(rangeID, 0))
-	// Replicate the range to store 2. The first range is no longer available on
-	// store 1, and this command will fail if that situation is not properly
-	// supported.
-	mtc.replicateRange(rangeID, 2)
-}
-
 // TestChangeReplicasDescriptorInvariant tests that a replica change aborts if
 // another change has been made to the RangeDescriptor since it was initiated.
 func TestChangeReplicasDescriptorInvariant(t *testing.T) {