oeqa.buildperf: add test Test2

Re-implement "test2" from build-perf-test.sh which measures
'bitbake core-image-sato -c rootfs'.

(From OE-Core rev: 8cb322d6a5be08f0bb2c9e5d3b73161b20d737a3)

Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/buildperf/basic_tests.py

@@ -69,3 +69,17 @@ class Test1P3(BuildPerfTest):
         finally:
             os.unlink(postfile)
         self.save_buildstats()
+
+
+@perf_test_case
+class Test2(BuildPerfTest):
+    name = "test2"
+    build_target = 'core-image-sato'
+    description = "Measure bitbake {} -c rootfs with sstate".format(build_target)
+
+    def _run(self):
+        self.rm_tmp()
+        self.rm_cache()
+        self.sync()
+        cmd = ['bitbake', self.build_target, '-c', 'rootfs']
+        self.measure_cmd_resources(cmd, 'do_rootfs', 'bitbake do_rootfs')