[continuous-integration] avoid coverage data loss (#4937)
[continuous-integration] avoid coverage data loss (#4937)

The code coverage data generated by ./script/test build expect will be
erased by VIRTUAL_TIME=0 NODE_MODE=rcp ./script/test clean build
expect's clean step, causing coverage less than actual value. This
adds an upload step after the first run to avoid the data loss.
chshu/openthread,chshu/openthread,librasungirl/openthread,librasungirl/openthread,bukepo/openthread,chshu/openthread,lanyuwen/openthread,bukepo/openthread,openthread/openthread,lanyuwen/openthread,openthread/openthread,openthread/openthread,srickardti/openthread,abtink/openthread,lanyuwen/openthread,lanyuwen/openthread,lanyuwen/openthread,chshu/openthread,abtink/openthread,bukepo/openthread,librasungirl/openthread,srickardti/openthread,jwhui/openthread,librasungirl/openthread,lanyuwen/openthread,abtink/openthread,openthread/openthread,bukepo/openthread,chshu/openthread,srickardti/openthread,jwhui/openthread,jwhui/openthread,srickardti/openthread,abtink/openthread,chshu/openthread,jwhui/openthread