sanitycheck: clarify who spawns processes and threads and where

Notably fix the wrong comment I added in commit 6f011c95c477: when
testing with QEmu sanitycheck does _not_ spawn QEmu; it relies on "make
run" instead.

Searching the code for "Spawning" now cycles directly to all the places
starting processes and threads.

- Sample -v -v verbose output (lines wrapped for commit message check)

 Spawning QEMUHandler Thread for \
     qemu_x86/samples/hello_world/sample.helloworld 'make run'

- native_posix example:

 Spawning process /home/.../sanity-out/native_posix/\
    /samples/hello_world/sample.helloworld/zephyr/zephyr.exe
 Spawning BinaryHandler Thread for native_posix/\
     samples/hello_world/sample.helloworld

Signed-off-by: Marc Herbert <marc.herbert@intel.com>
diff --git a/scripts/sanitycheck b/scripts/sanitycheck
index dc3f6b5..d4d913f 100755
--- a/scripts/sanitycheck
+++ b/scripts/sanitycheck
@@ -179,6 +179,7 @@
 import multiprocessing
 import select
 import shutil
+import shlex
 import signal
 import threading
 import time
@@ -570,7 +571,10 @@
                        "--log-file="+self.outdir+"/valgrind.log"
                        ] + command
 
+        verbose("Spawning process: " +
+                " ".join(shlex.quote(word) for word in command))
         with subprocess.Popen(command, stdout=subprocess.PIPE, stderr=subprocess.PIPE) as proc:
+            verbose("Spawning BinaryHandler Thread for %s" % self.name)
             t = threading.Thread(target=self._output_reader, args=(proc, harness, ))
             t.start()
             t.join(self.timeout)
@@ -854,7 +858,7 @@
 
         self.instance.results = harness.tests
         self.thread.daemon = True
-        verbose("Spawning QEMU process for %s" % self.name)
+        verbose("Spawning QEMUHandler Thread for %s 'make run'" % self.name)
         self.thread.start()
 
     def get_fifo(self):
@@ -1336,7 +1340,7 @@
             # Watch stderr output which is where we will keep
             # track of build state
             tf.write('\n# Generated by %s which is expected\n' % __file__)
-            tf.write('# to spawn qemu or testbinary, renode, etc. \n\n')
+            tf.write('# to create QEMU_PIPE, spawn zephyr.exe, etc. \n\n')
             for name, goal in sorted(self.goals.items()):
                 tf.write(goal.text)
             tf.write("all: %s\n" % (" ".join(sorted(self.goals.keys()))))