sim: testsuite: clean up arch specific toolchain settings

In a multitarget build, we process all targets in order, so make sure
the toolchain settings from one don't leak into the next.

sim/testsuite/example-synacor/allinsn.exp

@@ -17,6 +17,4 @@ if [istarget *] {
 	}
 	run_sim_test $src $all_machs
     }
-
-    unset LDFLAGS_FOR_TARGET
 }

sim/testsuite/lib/sim-defs.exp

@@ -46,10 +46,24 @@ proc sim_init { args } {
 proc sim_init_toolchain {} {
     global objdir
     global srcdir
+    global cpu_option
+    global cpu_option_sep
+    global ASFLAGS_FOR_TARGET
+    global CFLAGS_FOR_TARGET
+    global LDFLAGS_FOR_TARGET
+    global SIMFLAGS_FOR_TARGET
     global global_cpp_works
     global global_cc_works
     global global_cc_os
 
+    # Reset all the toolchain settings.  This provides a clean slate when
+    # starting the next set of tests.
+    set ASFLAGS_FOR_TARGET ""
+    set CFLAGS_FOR_TARGET ""
+    set LDFLAGS_FOR_TARGET ""
+    set SIMFLAGS_FOR_TARGET ""
+    unset -nocomplain cpu_option cpu_option_sep
+
     # See if we have a preprocessor available.
     set result [target_compile $srcdir/lib/compilercheck.c \
 		$objdir/compilercheck.x "preprocess" ""]

sim/testsuite/v850/allinsns.exp

@@ -21,6 +21,4 @@ if [istarget v850*-*] {
 	}
 	run_sim_test $src $all_machs
     }
-
-    unset cpu_option cpu_option_sep
 }