chg: pass --no-profile to disable profiling when starting hg serve

If profiling is enabled via global/user config (as far as I can tell, this
doesn't affect use of the --profile flag, but it probably does affect --config
profiling.enabled=1), then the profiling data can be *cumulative* for the
lifetime of the chg process.

This leads to some "interesting" results where hg claims the walltime is
something like 200s on a command that took only a second or two to run. Worse,
however, is that with at least some profilers (such as the default "stat"
profiler), this can cause a large slowdown while generating the profiler output.

Differential Revision: https://phab.mercurial-scm.org/D10470

contrib/chg/chg.c

@@ -242,6 +242,7 b' static void execcmdserver(const struct c'
 	const char *baseargv[] = {
 	    hgcmd,
 	    "serve",
+	    "--no-profile",
 	    "--cmdserver",
 	    "chgunix",
 	    "--address",

tests/test-chg.t

@@ -529,7 +529,7 b" FIXME: Run 4 should not be >3x Run 1's n"
   > EOF
   Run 1: * samples (glob)
   Run 4: * samples (glob)
-  Run 4 > 3 * Run 1: True
+  Run 4 > 3 * Run 1: False
 (Disabling with --no-profile on the commandline still works, but isn't permanent)
   $ newchg log -r . --no-profile
   $ filteredchg log -r .