Clean up temp files more thoroughly after testing. (#7815)

Our test cases spew a lot of files and directories around $TMPDIR.  Make more
thorough use of the testing package's TempDir methods to ensure these are
cleaned up.

In a few cases, this required plumbing test contexts through existing helper
code. In a couple places an explicit path was required, to work around cases
where we do global setup during a TestMain function. Those cases probably
deserve more thorough cleansing (preferably with fire), but for now I have just
worked around it to keep focused on the cleanup.

cmd/tendermint/commands/reindex_event_test.go

@@ -110,7 +110,7 @@ func TestLoadEventSink(t *testing.T) {
 }
 
 func TestLoadBlockStore(t *testing.T) {
-	testCfg, err := config.ResetTestRoot(t.Name())
+	testCfg, err := config.ResetTestRoot(t.TempDir(), t.Name())
 	require.NoError(t, err)
 	testCfg.DBBackend = "goleveldb"
 	_, _, err = loadStateAndBlockStore(testCfg)

cmd/tendermint/commands/rollback_test.go

@@ -19,7 +19,7 @@ func TestRollbackIntegration(t *testing.T) {
 	dir := t.TempDir()
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	cfg, err := rpctest.CreateConfig(t.Name())
+	cfg, err := rpctest.CreateConfig(t, t.Name())
 	require.NoError(t, err)
 	cfg.BaseConfig.DBBackend = "goleveldb"