native_posix: enable coverage by default
native_posix: enable coverage by default

To get coverage data from all samples and tests, enable this by default.
Right now we only get coverage data from tests, however many samples we
currently have can run natively and can generate more coverage and
testing.

This should be removed once we have tests provide better coverage.

Signed-off-by: Anas Nashif <0d9952ec84ac43c159f6b7e7ed99a9080c00dd6e@intel.com>

explora26/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,Vudentz/zephyr,Vudentz/zephyr,punitvara/zephyr,punitvara/zephyr,finikorg/zephyr,explora26/zephyr,GiulianoFranchetto/zephyr,kraj/zephyr,zephyriot/zephyr,ldts/zephyr,kraj/zephyr,galak/zephyr,nashif/zephyr,kraj/zephyr,Vudentz/zephyr,punitvara/zephyr,finikorg/zephyr,zephyriot/zephyr,nashif/zephyr,mbolivar/zephyr,zephyriot/zephyr,ldts/zephyr,Vudentz/zephyr,mbolivar/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,finikorg/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,mbolivar/zephyr,explora26/zephyr,zephyrproject-rtos/zephyr,kraj/zephyr,mbolivar/zephyr,zephyriot/zephyr,mbolivar/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,zephyriot/zephyr,Vudentz/zephyr,explora26/zephyr,galak/zephyr,Vudentz/zephyr,explora26/zephyr,nashif/zephyr,ldts/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,punitvara/zephyr,kraj/zephyr,GiulianoFranchetto/zephyr,punitvara/zephyr,finikorg/zephyr,nashif/zephyr