When an error occured during setup web execution, test steps linked must be not executed

[kevinramage]

Scope: Web executor
Expected: When an error occured during setup web execution, test steps linked must be not executed
Actual: When you have create a web test with several test steps and you have an issue during setup step (driver not present for example)

Root cause: "process_testcase.go"
knowExecutors variable msut be set before setup call if there are no errors
RunTestStep function must be called only if setup function call successfully