IMAGE_allocate will attempt to load a nonexistent file, causing a crash

[scholar-mage]

Dome will attempt to load invalid resource paths, which causes a segfault. For example, rename ship1.png to something else, and you'll get the following crash:

Loading module audio
Loading module input
Loading module graphics
Loading module point
Loading module random
Loading module io

Thread 1 "dome" received signal SIGSEGV, Segmentation fault.
0x000055555556ed75 in stbi__get8 (s=0x7fffffffbb30) at src/include/stb_image.h:1409
1409	      return *s->img_buffer++;
(gdb) where
#0  0x000055555556ed75 in stbi__get8 (s=0x7fffffffbb30) at src/include/stb_image.h:1409
#1  0x0000555555575e26 in stbi__get_marker (j=0x5555576b5500) at src/include/stb_image.h:2660
#2  0x000055555557866c in stbi__decode_jpeg_header (z=0x5555576b5500, scan=1)
    at src/include/stb_image.h:3098
#3  0x000055555557bc04 in stbi__jpeg_test (s=0x7fffffffbb30) at src/include/stb_image.h:3750
#4  0x000055555556dc4f in stbi__load_main (s=0x7fffffffbb30, x=0x5555576b54d8, y=0x5555576b54dc, 
    comp=0x5555576b54e0, req_comp=4, ri=0x7fffffffbadc, bpc=8) at src/include/stb_image.h:980
#5  0x000055555556e0c9 in stbi__load_and_postprocess_8bit (s=0x7fffffffbb30, x=0x5555576b54d8, 
    y=0x5555576b54dc, comp=0x5555576b54e0, req_comp=4) at src/include/stb_image.h:1088
#6  0x000055555556e7ec in stbi_load_from_memory (buffer=0x0, len=1431883287, x=0x5555576b54d8, 
    y=0x5555576b54dc, comp=0x5555576b54e0, req_comp=4) at src/include/stb_image.h:1226
#7  0x0000555555567f5e in IMAGE_allocate (vm=0x5555575c2c20) at src/engine/image.c:19
#8  0x000055555558b3ff in runInterpreter ()
#9  0x0000555555569deb in main (argc=1, args=0x7fffffffde58) at src/main.c:172

[avivbeeri]

This is fixed for asset loading, but will need to be revisited when async loading is introduced.