Improve handling of -short flag in tests (#9075)

As a small developer quality of life improvement, I found many individual unit tests that take longer than around a second to complete, and set them to skip when run under `go test -short`.

On my machine, the wall timings for tests (with `go test -count=1 ./...` and optionally `-short` and `-race`) are roughly:

- Long tests, no race detector: about 1m42s
- Short tests, no race detector: about 17s
- Long tests, race detector enabled: about 2m1s
- Short tests, race detector enabled: about 28s

This PR is split into many commits each touching a single package, with commit messages detailing the approximate timing change per package.

node/node_test.go

@@ -106,6 +106,10 @@ func getTestNode(ctx context.Context, t *testing.T, conf *config.Config, logger
 }
 
 func TestNodeDelayedStart(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode")
+	}
+
 	cfg, err := config.ResetTestRoot(t.TempDir(), "node_delayed_start_test")
 	require.NoError(t, err)
 
@@ -195,6 +199,10 @@ func TestNodeSetPrivValTCP(t *testing.T) {
 
 // address without a protocol must result in error
 func TestPrivValidatorListenAddrNoProtocol(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode")
+	}
+
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
@@ -441,6 +449,10 @@ func TestMaxTxsProposalBlockSize(t *testing.T) {
 }
 
 func TestMaxProposalBlockSize(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode")
+	}
+
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()