Embedded GDScript crashes player

[GiantBlargg]

Godot version: 3811fb9

OS/device including version: Manjaro Linux

Issue description:
Playing a scene containing an embedded GDScript causes a crash:

Godot Engine v4.0.dev.custom_build.3811fb919 - https://godotengine.org
DisplayServer::_create_window 0 want rect: 448, 240, 1024, 600 got rect 0, 0, 1024, 600
DisplayServer::_window_changed: 0 rect: 1920, 450, 1024, 600
 
ERROR: Condition "err" is true. Returning: err
   at: load_source_code (modules/gdscript/gdscript.cpp:825)
ERROR: res://Node.tscn:23 - Parse Error: Can't load cached sub-resource: res://Node.tscn::1
   at: _parse_node_tag (scene/resources/resource_format_text.cpp:282)
ERROR: Failed loading resource: res://Node.tscn.
   at: _load (core/io/resource_loader.cpp:198)
ERROR: Failed loading scene: res://Node.tscn
   at: start (main/main.cpp:2030)
ERROR: 1 RID allocations of type 'P11SpaceBullet' were leaked at exit.
ERROR: 1 RID allocations of type 'P8Area2DSW' were leaked at exit.
ERROR: 1 RID allocations of type 'P9Space2DSW' were leaked at exit.
ERROR: 1 RID allocations of type 'N17RasterizerSceneRD11EnvironmentE' were leaked at exit.
ERROR: 2 RID allocations of type 'N17RasterizerSceneRD11ShadowAtlasE' were leaked at exit.
ERROR: 1 RID allocations of type 'N17RasterizerSceneRD15ReflectionAtlasE' were leaked at exit.
ERROR: 1 RID allocations of type 'N17RasterizerSceneRD3SkyE' were leaked at exit.
ERROR: 1 RID allocations of type 'N19RasterizerStorageRD12RenderTargetE' were leaked at exit.
ERROR: 2 RID allocations of type 'N19RasterizerStorageRD7TextureE' were leaked at exit.
ERROR: 1 RID allocations of type 'PN21RenderingServerCanvas6CanvasE' were leaked at exit.
ERROR: 1 RID allocations of type 'PN23RenderingServerViewport8ViewportE' were leaked at exit.
ERROR: 1 RID allocations of type 'PN20RenderingServerScene8ScenarioE' were leaked at exit.
WARNING: 6 RIDs of type 'Texture' were leaked.
     at: finalize (drivers/vulkan/rendering_device_vulkan.cpp:7486)
WARNING: ObjectDB instances leaked at exit (run with --verbose for details).
     at: cleanup (core/object.cpp:2041)
ERROR: Resources still in use at exit (run with --verbose for details).
   at: clear (core/resource.cpp:435)

This only happens with GDScript and not other embedded resources.

Likely introduced with #40598

Minimal reproduction project:
Embedded GDScript.zip

[GiantBlargg]

@vnen