Unconditional add vhpi options to Xcelium simulator

[IgorAmosov]

cocotb-test/cocotb_test/simulator.py

Line 718 in 32b19b0

self.env["GPI_EXTRA"] = cocotb.config.lib_name_path("vhpi", "xcelium") + ":cocotbvhpi_entry_point"

Hello! Please, explain me, why vhpi option for vhdl_source is added to xcelium in unconditional way?
I don't use any vhdl source, but VHPI option generates additional errors in simuation.
I've looked through simulator.py and find that vhpi add to options for other simulators only if vhdl_source is preset.
I'he commented this line and my sv project works fine =)

[themperek]

This can be changed. Can you make a PR?