Avoid test timeouts on slower hosts like e.g. ia64 (guppy):
```
FAILED jupyter_client/tests/test_kernelmanager.py::TestParallel::test_start_sequence_kernels[tcp] - Failed: Timeout >30.0s
FAILED jupyter_client/tests/test_kernelmanager.py::TestParallel::test_start_sequence_kernels[ipc] - Failed: Timeout >30.0s
```
--- a/jupyter_client/tests/test_client.py
+++ b/jupyter_client/tests/test_client.py
@@ -13,7 +13,7 @@ from jupyter_client.kernelspec import KernelSpecManager
 from jupyter_client.kernelspec import NATIVE_KERNEL_NAME
 from jupyter_client.kernelspec import NoSuchKernel
 
-TIMEOUT = 30
+TIMEOUT = 180
 
 pjoin = os.path.join
 
--- a/jupyter_client/tests/test_kernelmanager.py
+++ b/jupyter_client/tests/test_kernelmanager.py
@@ -24,7 +24,7 @@ from jupyter_client import KernelManager
 
 pjoin = os.path.join
 
-TIMEOUT = 30
+TIMEOUT = 180
 
 
 @pytest.fixture(params=["tcp", "ipc"])
--- a/jupyter_client/tests/test_multikernelmanager.py
+++ b/jupyter_client/tests/test_multikernelmanager.py
@@ -22,7 +22,7 @@ from jupyter_client import KernelManager
 from jupyter_client.multikernelmanager import AsyncMultiKernelManager
 from jupyter_client.multikernelmanager import MultiKernelManager
 
-TIMEOUT = 30
+TIMEOUT = 180
 
 
 class TestKernelManager(TestCase):