add tfm to the default format of trx file

[nohwnd]

#5141 naming the trx with the assembly name + tfm should disambiguate it nicely for multi tfm runs. instead of getting names like this:

[MihuBot]

I'm a bot. Here is a possible related and/or duplicate issue (I may be wrong):

• Using TrxReport with --test-modules should include test assembly name and target framework in trx file name testfx#7345