[AArch64] [test] Spell out the matching instructions for SVE unwind opcodes

The MS dumpbin.exe tool can dump the unwind opcodes with the
"-unwindinfo" option; this mode also checks that the instructions
actually match the expected ones here. (This mode doesn't seem
to fully work for all instructions here, but spell out all the
intended instructions here.)

Author: mstorsjo

llvm/test/MC/AArch64/seh.s

@@ -131,6 +131,8 @@
 // CHECK-NEXT: ]
 
 
+    .arch_extension sve
+
     .text
     .globl func
     .def func
@@ -177,35 +179,35 @@ func:
     .seh_nop
     pacibsp
     .seh_pac_sign_lr
-    nop
+    str x0, [sp, #64]
     .seh_save_any_reg x0, 64
-    nop
+    stp x1, x2, [sp, #64]
     .seh_save_any_reg_p x1, 64
-    nop
+    str d29, [sp, #64]
     .seh_save_any_reg d29, 64
-    nop
+    stp d4, d5, [sp, #64]
     .seh_save_any_reg_p d4, 64
-    nop
+    str q30, [sp, #64]
     .seh_save_any_reg q30, 64
-    nop
+    stp q3, q4, [sp, #64]
     .seh_save_any_reg_p q3, 64
-    nop
+    str x30, [sp, #-64]!
     .seh_save_any_reg_x lr, 64
-    nop
+    stp x29, x30, [sp, #-64]!
     .seh_save_any_reg_px fp, 64
-    nop
+    str d31, [sp, #-64]!
     .seh_save_any_reg_x d31, 64
-    nop
+    stp d2, d3, [sp, #-64]!
     .seh_save_any_reg_px d2, 64
-    nop
+    str q29, [sp, #-64]!
     .seh_save_any_reg_x q29, 64
-    nop
+    stp q9, q10, [sp, #-64]!
     .seh_save_any_reg_px q9, 64
-    nop
+    addvl sp, sp, #-5
     .seh_allocz 5
-    nop
+    str z11, [sp, #5, mul vl]
     .seh_save_zreg z11, 5
-    nop
+    str p6, [sp, #3, mul vl]
     .seh_save_preg p6, 3
     .seh_endprologue
     nop