test: evm signer unstable

[gartnera]

I often see these errors in the unit tests:

--- FAIL: TestSigner_SignConnectorOnReceive (0.00s)
    --- FAIL: TestSigner_SignConnectorOnReceive/SignConnectorOnReceive_-_should_successfully_sign (0.00s)
        signer_test.go:123: 
            	Error Trace:	/home/runner/work/node/node/zetaclient/chains/evm/signer/signer_test.go:123
            	            				/home/runner/work/node/node/zetaclient/chains/evm/signer/sign_test.go:37
            	Error:      	Should be true
            	Test:       	TestSigner_SignConnectorOnReceive/SignConnectorOnReceive_-_should_successfully_sign
    --- FAIL: TestSigner_SignConnectorOnReceive/SignOutbound_-_should_successfully_sign_LegacyTx (0.00s)
        signer_test.go:123: 
            	Error Trace:	/home/runner/work/node/node/zetaclient/chains/evm/signer/signer_test.go:123
            	            				/home/runner/work/node/node/zetaclient/chains/evm/signer/sign_test.go:57
            	Error:      	Should be true
            	Test:       	TestSigner_SignConnectorOnReceive/SignOutbound_-_should_successfully_sign_LegacyTx

--- FAIL: TestSigner_SignAdminTx (0.00s)
    --- FAIL: TestSigner_SignAdminTx/SignAdminTx_CmdWhitelistERC20 (0.00s)
        signer_test.go:123: 
            	Error Trace:	/home/runner/work/node/node/zetaclient/chains/evm/signer/signer_test.go:123
            	            				/home/runner/work/node/node/zetaclient/chains/evm/signer/signer_admin_test.go:40
            	Error:      	Should be true
            	Test:       	TestSigner_SignAdminTx/SignAdminTx_CmdWhitelistERC20

[lumtis]

Yeah it's been happening for a long time, it's not a recent change that caused this FWIW