Match the working directory on remote host

The test in gdb.python/python.exp tests "extended-prompt" and expects
working directory is printed.  However, working directory on remote
host doesn't have "gdb/testsuite", so the test fails on remote host
like:

set extended-prompt \w ^M
^M
/home/yao FAIL: gdb.python/python.exp: set extended prompt working directory (timeout)

This patch is to get the working directory first, and use it to match
the output of "set extended-prompt \\w ".  It works for remote host
and non remote host.

gdb/testsuite:

2014-11-02  Yao Qi  <yao@codesourcery.com>

	* gdb.python/python.exp: Get working directory and match the
	output of "set extended-prompt \\w " with it.

gdb/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2014-11-02  Yao Qi  <yao@codesourcery.com>
+
+	* gdb.python/python.exp: Get working directory and match the
+	output of "set extended-prompt \\w " with it.
+
 2014-10-30  Doug Evans  <dje@google.com>
 
 	* gdb.python/py-objfile.exp: Add tests for setting random attributes

gdb/testsuite/gdb.python/python.exp

@@ -314,6 +314,13 @@ gdb_test_multiple "set prompt $gdb_prompt " "set default prompt" {
     }
 }
 
+set working_dir ""
+gdb_test_multiple "pwd" "pwd" {
+    -re "Working directory (.*)\\.\[\r\n\]+$gdb_prompt $" {
+	set working_dir $expect_out(1,string)
+    }
+}
+
 gdb_test_multiple "python gdb.prompt_hook = program_prompt" "set the hook" {
     -re "\[\r\n\]$gdb_prompt $" {
 	pass "set programming hook"
@@ -346,7 +353,7 @@ gdb_test_multiple "set extended-prompt one two three " \
 
 gdb_test_multiple "set extended-prompt \\w " \
     "set extended prompt working directory" {
-    -re "\[\r\n\].*gdb.*testsuite.* $" {
+    -re "\[\r\n\][string_to_regexp $working_dir] $" {
 	pass "set extended prompt working directory"
     }
 }