[gdb/testsuite] get_valueof: Don't output value in test name

[gdb/testsuite] get_valueof: Don't output value in test name

The get_valueof outputs the value it has read as part of the test name.  This
causes test names to vary from run to run, and adds some noise when diffing
test results.  e.g.:

-PASS: gdb.guile/scm-ports.exp: buffered: get valueof "$sp" (140737488343920)
+PASS: gdb.guile/scm-ports.exp: buffered: get valueof "$sp" (140737488343968)
-PASS: gdb.guile/scm-ports.exp: unbuffered: get valueof "$sp" (140737488343920)
+PASS: gdb.guile/scm-ports.exp: unbuffered: get valueof "$sp" (140737488343968)

This patch removes that, since it's probably not very useful.

Tested on x86_64-linux.

2018-10-31  Tom de Vries  <tdevries@suse.de>

	* lib/gdb.exp (get_valueof): Don't output read value in test name.