Compile break-asm-file{0,1}.s without debug info

Compile break-asm-file{0,1}.s without debug info

If I add some nop into break-asm-file1.s like this,

--- INDEX:/gdb/testsuite/gdb.linespec/break-asm-file1.s
+++ WORKDIR:/gdb/testsuite/gdb.linespec/break-asm-file1.s
@@ -31,8 +31,8 @@ _func:
 	.type func, %function
 func:
 .Lbegin_func:
-	.int 0
-	.int 0
+	nop
+	nop
 .Lend_func:
 	.size func, .-func
 .Lend_text1:

I get the following error:

Running gdb/testsuite/gdb.linespec/break-asm-file.exp ...
gdb/testsuite/gdb.linespec/break-asm-file1.s: Assembler messages:^M
gdb/testsuite/gdb.linespec/break-asm-file1.s: Fatal error: duplicate .debug_line sections

break-asm-file0.s and break-asm-file1.s have already had debug information
(written manually), so don't need to generate debug infor for them.

gdb/testsuite:

2015-03-26  Yao Qi  <yao.qi@linaro.org>

	* gdb.linespec/break-asm-file.exp: Don't call prepare_for_testing.
	Call gdb_compile instead to compile each .s files without debug
	information.