Use standard_testfile in i386-bp_permanent.exp

Use standard_testfile in i386-bp_permanent.exp

This patch is to use standard_testfile in i386-bp_permanent.exp to replace
existing setting to testfile, srcfile and binfile.  So it fixes a problem
in i386-bp_permanent.exp in parallel testing.

$ make -j3 check TESTS='gdb.guile/scm-section-script.exp gdb.arch/i386-bp_permanent.exp'
....
gdb compile failed, /usr/bin/ld: cannot open output file x86/gdb/testsuite/gdb.arch/i386-bp_permanent: No such file or directory
collect2: error: ld returned 1 exit status

gdb/testsuite:

2014-12-05  Yao Qi  <yao@codesourcery.com>

	* gdb.arch/i386-bp_permanent.exp: Use standard_testfile.