[BOLT] Fix section-end-sym.s test to only run x86/Linux

section-end-sym.s contains x86_64 assembly instruction execution on target.
I have changed REQURIES: field system-linux --> x86_64-linux
This came up while testing LLVM 16.0.1 release on AArch64 Linux.

Author: omjavaid

bolt/test/X86/section-end-sym.s

@@ -1,7 +1,7 @@
 ## Check that BOLT doesn't consider end-of-section symbols (e.g., _etext) as
 ## functions.
 
-# REQUIRES: system-linux, asserts
+# REQUIRES: x86_64-linux, asserts
 
 # RUN: llvm-mc -filetype=obj -triple x86_64-unknown-linux %s -o %t.o
 # RUN: ld.lld %t.o -o %t.exe -q