[Bug target/85005] Redesign and cleanup arm.c wrt to flag_stack_clash_protection and flag_stack_check

[sudi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85005

sudi at gcc dot gnu.org changed:

           What    |Removed                     |Added
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             Target|                            |arm*-*-*
                 CC|                            |wilco at gcc dot gnu.org
   Target Milestone|---                         |9.0