!773 Compiler: Add value profile support for kernel.

Merge Pull Request from: @xiongzhou4 
 
Provides value profile support for kernel.
The implementation is based on the existing GCOV feature of the kernel. When the option is opened, the GCOV option `-fprofile-arcs` is changed to `-fprofile-generate`. The latter includes the former and value profile, which can provide more comprehensive feedback directed optimization ability.
The added feature is called  _PGO kernel_ , which can be used to improve the performance of a single application runtime environment.

kernel option(default is n):
CONFIG_PGO_KERNEL=y 
 
Link:https://gitee.com/openeuler/kernel/pulls/773

 

Reviewed-by: Liu Chao <liuchao173@huawei.com>
Reviewed-by: Zheng Zengkai <zhengzengkai@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>