Separate ssa_struct_gep and ssa_array_gep procedures

src/string.cpp

@@ -3,7 +3,7 @@ gb_global gbAllocator string_buffer_allocator = {};
 
 void init_string_buffer_memory(void) {
 	// NOTE(bill): This should be enough memory for file systems
-	gb_arena_init_from_allocator(&string_buffer_arena, gb_heap_allocator(), gb_megabytes(1));
+	gb_arena_init_from_allocator(&string_buffer_arena, heap_allocator(), gb_megabytes(1));
 	string_buffer_allocator = gb_arena_allocator(&string_buffer_arena);
 }