Fix bogus gdb_test invocations

A following patch will make gdb_test error out if bogus arguments are
passed, which exposed bugs in a few testcases:

 - gdb.python/py-parameter.exp, passing a spurious "1" as extra
   parameter, resulting in:

   ERROR: Unexpected arguments: {set test-file-param bar.txt} {The name of the file has been changed to bar.txt} {set new file parameter} 1

 - gdb.python/py-xmethods.exp, a missing test message, resulting in
   the next gdb_test being interpreted as message, question and
   response!  With the enforcing patch, this was caught with:

   ERROR: Unexpected arguments: {p g.mul<char>('a')} {From Python G<>::mul.*} gdb_test {p g_ptr->mul<char>('a')} {From Python G<>::mul.*} {after: g_ptr->mul<char>('a')}

 - gdb.base/pointers.exp, missing a quote.

Change-Id: I66f2db4412025a64121db7347dfb0b48240d46d4

gdb/testsuite/gdb.python/py-parameter.exp

@@ -199,7 +199,7 @@ proc_with_prefix test_file_parameter { } {
 	"The name of the file is foo.txt.*" "show initial file value"
     gdb_test "set test-file-param bar.txt" \
 	"The name of the file has been changed to bar.txt" \
-	"set new file parameter" 1
+	"set new file parameter"
     gdb_test "show test-file-param" \
 	"The name of the file is bar.txt.*" "show new file value"
     gdb_test "python print (test_file_param.value)" \

gdb/testsuite/gdb.python/py-xmethods.exp

@@ -130,6 +130,7 @@ gdb_test "p g.size_mul<  5  >()" "From Python G<>::size_mul.*" \
 gdb_test "p g.mul<double>(2.0)" "From Python G<>::mul.*" \
   "after: g.mul<double>(2.0)"
 gdb_test "p g.mul<char>('a')" "From Python G<>::mul.*" \
+  "after: g.mul<char>('a')"
 gdb_test "p g_ptr->mul<char>('a')" "From Python G<>::mul.*" \
   "after: g_ptr->mul<char>('a')"