Only exclude RTOS-specifc tests in error_handling
Only exclude RTOS-specifc tests in error_handling

Allows for other tests to run if no RTOS is present.
c1728p9/mbed-os,andcor02/mbed-os,betzw/mbed-os,kjbracey-arm/mbed,c1728p9/mbed-os,andcor02/mbed-os,kjbracey-arm/mbed,mbedmicro/mbed,mbedmicro/mbed,kjbracey-arm/mbed,c1728p9/mbed-os,betzw/mbed-os,mbedmicro/mbed,mbedmicro/mbed,c1728p9/mbed-os,betzw/mbed-os,betzw/mbed-os,betzw/mbed-os,andcor02/mbed-os,c1728p9/mbed-os,mbedmicro/mbed,andcor02/mbed-os,andcor02/mbed-os,c1728p9/mbed-os,betzw/mbed-os,kjbracey-arm/mbed,andcor02/mbed-os