[PATCH][AARCH64] Fix for PR94121

[lizekun (A)]

Hi,

This is a fix tring to solve PR94121.

The ICE appears when generating an add insn with the offset. If the offset is negative, function aarch64_add_offset_1 in aarch64.c will take its absolute value.
With this fix, offset does not take absolute value if it equals to the minimum value of machine.

Added one test case for this. Bootstrap and tested on aarch64 Linux platform.  

Zekun Li


Log:
	PR 94121
	* aarch64.c (aarch64_add_offset_1): Add a branch 
	when generating addition assembly expression with 
	offset HOST_WIDE_INT_MIN.
	* gcc.target/aarch64/PR94121.c: New test.