revert back to parallel #552

Job	Run time
Test node:parallel:local client against server:node	7m 52s
Test node:parallel:local client against server:node	4m 17s
Test node:parallel:local client against server:node	2m 15s
Test node:parallel:local client against server:node	2m 15s
Test node:parallel:remote client against server:node	3m 11s
Test node:parallel:remote client against server:node	3m 11s
Test node:parallel:remote client against server:node	3m 11s
Test node:parallel:remote client against server:node	3m 11s
Test node:rpc client against server:node	8m 8s
Test node:rpc client against server:node	8m 8s
Test node:rpc client against server:node	20m 13s
Test node:rpc client against server:node	8m 32s
Test browser:firefox client against server:node	8m 10s
Test browser:firefox client against server:node	8m 10s
Test browser:firefox client against server:node	11m 55s
Test browser:firefox client against server:node	11m 55s
Test browser:chrome client against server:node	8m 10s
Test browser:chrome client against server:node	8m 10s
Test browser:chrome client against server:node	9m 29s
Test browser:chrome client against server:node	9m 29s
test-plebbit-protocol-test / test	4m 5s
test-plebbit-protocol-test / test	4m 5s
test-plebbit-protocol-test / test	3m 40s
test-plebbit-protocol-test / test	3m 40s
test-plebbit-react-hooks / test	5m 58s
test-plebbit-react-hooks / test	5m 58s
test-plebbit-react-hooks / test	5m 58s
test-plebbit-react-hooks / test	5m 58s
	3h 9m 14s

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