sim: cris: fix testsuite hang when sim is missing

If the cris sim hasn't been built yet, trying to run its testsuite
will hang indefinitely.  The common sim APIs already have this, so
copy it over to the cris forks of the test+run functions.

sim/testsuite/cris/c/c.exp

@@ -94,6 +94,11 @@ foreach src [lsort [glob -nocomplain $srcdir/$subdir/*.c]] {
 	continue
     }
 
+    if ![file exists [sim_tool_path]] {
+	untested $testname
+	return 0
+    }
+
     # Clear default options
     set opts(cc) ""
     set opts(sim) ""

sim/testsuite/cris/hw/rv-n-cris/rvc.exp

@@ -24,6 +24,10 @@ proc sim_has_rv_and_cris {} {
     global objdir
     global SIMFLAGS_FOR_TARGET
 
+    if ![file exists [sim_tool_path]] {
+	return 0
+    }
+
     # We need to assemble and link a trivial program and pass that, in
     # order to test successful exit.