[bcl] Replace nunit24 with nunit-lite

[bcl] Replace nunit24 with nunit-lite

Get rid of TEST_HARNESS_VERBOSE and enable verbose logging by default

nunit-lite doesn't have the "dot when test runs" progress indicator anymore,
so we need to enable "verbose" output by default otherwise we don't get
any progress until the test run is over.

Also remove the TestResult_$(PROFILE).log and nunit-summary.xsl files,
they're not needed anymore.