fix stack local offset size for passing argument (dotnet#101103)

src/mono/mono/mini/mini-s390x.c

@@ -1580,7 +1580,7 @@ mono_arch_allocate_vars (MonoCompile *cfg)
 						inst->inst_offset  = offset + (8 - size);
 				}
 			}
-			offset += MAX(size, 8);
+			offset += 8;
 		}
 		curinst++;
 	}