Fix unstable test names in gdb.base/startup-with-shell.exp

Currently, if you diff testsuite/gdb.sum of two builds in different
directories you see these spurious hunks:

  -PASS: gdb.base/startup-with-shell.exp: touch /home/pedro/gdb1/build/gdb/testsuite/outputs/gdb.base/startup-with-shell/unique-file.unique-extension
  +PASS: gdb.base/startup-with-shell.exp: touch /home/pedro/gdb2/build/gdb/testsuite/outputs/gdb.base/startup-with-shell/unique-file.unique-extension

  -PASS: gdb.base/startup-with-shell.exp: startup_with_shell = on; run_args = *.unique-extension: set args /home/pedro/gdb1/build/gdb/testsuite/outputs/gdb.base/startup-with-shell/*.unique-extension
  +PASS: gdb.base/startup-with-shell.exp: startup_with_shell = on; run_args = *.unique-extension: set args /home/pedro/gdb2/build/gdb/testsuite/outputs/gdb.base/startup-with-shell/*.unique-extension

  -PASS: gdb.base/startup-with-shell.exp: startup_with_shell = off; run_args = *.unique-extension: set args /home/pedro/gdb1/build/gdb/testsuite/outputs/gdb.base/startup-with-shell/*.unique-extension
  +PASS: gdb.base/startup-with-shell.exp: startup_with_shell = off; run_args = *.unique-extension: set args /home/pedro/gdb2/build/gdb/testsuite/outputs/gdb.base/startup-with-shell/*.unique-extension

Since the run_args arguments are already shown in the test prefix, we
can change the "set args" test name to literally "set args $run_args".
I.e., after this commit we'll show:

  PASS: gdb.base/startup-with-shell.exp: startup_with_shell = on; run_args = *.unique-extension: set args $run_args
  PASS: gdb.base/startup-with-shell.exp: startup_with_shell = off; run_args = *.unique-extension: set args $run_args
  PASS: gdb.base/startup-with-shell.exp: startup_with_shell = on; run_args = $TEST: set args $run_args
  PASS: gdb.base/startup-with-shell.exp: startup_with_shell = off; run_args = $TEST: set args $run_args

gdb/testsuite/ChangeLog:
2017-10-24  Pedro Alves  <palves@redhat.com>

	* gdb.base/startup-with-shell.exp ('touch $unique_file'): Don't
	include the unstable output directory name in the test's name.
	(initial_setup_simple) <'set args'>: Use custom test name.

2 files changed, 11 insertions, 2 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index a8c4d81..36c2b95 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,5 +1,11 @@
 2017-10-24  Pedro Alves  <palves@redhat.com>
 
+	* gdb.base/startup-with-shell.exp ('touch $unique_file'): Don't
+	include the unstable output directory name in the test's name.
+	(initial_setup_simple) <'set args'>: Use custom test name.
+
+2017-10-24  Pedro Alves  <palves@redhat.com>
+
 	* gdb.arch/arc-tdesc-cpu.exp ('set tdesc filename'): Use gdb_test
 	with explicit test name.
 
diff --git a/gdb/testsuite/gdb.base/startup-with-shell.exp b/gdb/testsuite/gdb.base/startup-with-shell.exp
index af06c88..29a4ec5 100644
--- a/gdb/testsuite/gdb.base/startup-with-shell.exp
+++ b/gdb/testsuite/gdb.base/startup-with-shell.exp
@@ -37,7 +37,9 @@ if { [prepare_for_testing "failed to prepare" $testfile $srcfile debug] } {
 set unique_file [standard_output_file "unique-file.unique-extension"]
 set unique_file_dir [standard_output_file ""]
 
-run_on_host "touch $unique_file" "touch" "$unique_file"
+run_on_host \
+    "touch OUTPUT_DIR/unique-file.unique-extension" \
+    "touch" "$unique_file"
 
 # Initial setup for simple test (wildcard expansion, variable substitution).
 
@@ -48,7 +50,8 @@ proc initial_setup_simple { startup_with_shell run_args } {
 
     gdb_test_no_output "set startup-with-shell $startup_with_shell"
 
-    gdb_test_no_output "set args $run_args"
+    gdb_test_no_output "set args $run_args" \
+	"set args \$run_args"
 
     set test "inferior started"
     if { [runto_main] } {