apps/blemesh: Keep track of allowed and recent test id
apps/blemesh: Keep track of allowed and recent test id

According to the spec test id parameter returned by Health Fault Status
should be the id of the most recently performed test.

Value 0x00 stands for Standard Test. Any other value is Vendor specific
test.

This is required by MESH/SR/HM/RFS/BI-01-C. PTS checks if IUT
ignores Health Fault Test message with invalid test id.

andrzej-kaczmarek/incubator-mynewt-core,mlaz/mynewt-core,andrzej-kaczmarek/apache-mynewt-core,IMGJulian/incubator-mynewt-core,IMGJulian/incubator-mynewt-core,IMGJulian/incubator-mynewt-core,IMGJulian/incubator-mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,IMGJulian/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,mlaz/mynewt-core,mlaz/mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,andrzej-kaczmarek/incubator-mynewt-core