Create tests for pending state

[tclemos]

We need to create tests consuming the following methods for the pending block in order to make sure the behavior is as expected when consuming the trusted state

• eth_call
• eth_estimateGas
• eth_getBalance
• eth_getCode
• eth_getStorageAt

[arnaubennassar]

@tclemos it should be relatively easy to extend this test to cover the endpoint you mention