Change the message sent to IntelliJ when starting the test suites to the correct one

[helomri]

This is the cause of the error mentioned in #8325.
Previously, the correct message was being sent hard-coded and was supposed to be replaced by ServiceMessageBuilder.testsStarted() once the method was available. Instead, ServiceMessageBuilder.testStarted("") was used which changes the message to ##teamcity[testStarted name=''] from ##teamcity[enteredtheMatrix] (hence the error).

This one-liner just replaces the erroneous call to the correct one.

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