Use it in diagnostic tests with JVM backend instead of the
RENDER_DIAGNOSTICS_FULL_TEXT directive.
This is needed because otherwise in
AbstractDiagnosticsTestWithJvmBackend there are two handlers trying to
dump full diagnostic texts: JvmBackendDiagnosticsHandler and
FirDiagnosticsHandler, which dump different diagnostics (reported by
backend vs frontend) and in slightly different formats.
In fact, this is why exceptionFromInterpreter.fir.diag.txt was added in
48484368c7: the existing .diag.txt was detected as incorrect by
FirDiagnosticsHandler (even though the diagnostics are the same, just
printed in a different way), which led to the creation of .fir.diag.txt.
For these tests, the behavior about checking diagnostic text in
FirDiagnosticsHandler is useless because it doesn't include backend
diagnostics. So we disable it by using another directive.
Alexander Udalov