core: fix process exit status code

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

src/Core.zig

@@ -315,7 +315,7 @@ pub fn start(core: *Mod) !void {
         }
         // Don't return, because Platform.run wouldn't either (marked noreturn due to underlying
         // platform APIs never returning.)
-        std.process.exit(1);
+        std.process.exit(0);
     } else {
         // Platform drives the main loop.
         Platform.run(platform_update_callback, .{ &mach.mods.mod.mach_core, stack_space });
@@ -323,7 +323,7 @@ pub fn start(core: *Mod) !void {
         // Platform.run should be marked noreturn, so this shouldn't ever run. But just in case we
         // accidentally introduce a different Platform.run in the future, we put an exit here for
         // good measure.
-        std.process.exit(1);
+        std.process.exit(0);
     }
 }