Flickering/Possible Sync issue when reusing index buffer on Metal

[oxue]

Describe the bug
have 2 draw calls per frame
Reuse index buffer with differently "alignment" so go 012 123 for the first draw and 012345 for second draw call.

we see flickering on Metal but not on HTML5.

basically I thinkn index buffer is corrupted between the draw calls.

here is an example: https://github.com/oxue/kha_repro_1

To Reproduce
https://github.com/oxue/kha_repro_1

have 2 draw calls per frame
Reuse index buffer with differently "alignment" so go 012 123 for the first draw and 012345 for second draw call.

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots

THAT smiley on the left should not be triangle.

Execution Environment:

• Host system (where you compile your code): macosx
• Target system (where you run your code): macosx
• IDE used (if any): vscode
• Kha revision: 23.8.0
• Kha build output (Using Kha...):
• Application output (if it runs):

Additional context
Add any other context about the problem here.