Fix CFrameActionMngr (RequestFrame) not being cleared

[Th3-822]

The fix looks like a workaround because there is no clear method in amtl/am-deque.h and i don't know if i can or how to call it directly

if i were better at C stuff i could make a pr to add a clear method on am-deque first

Fixes #1039, also don't forget to apply it to 1.9-dev too

[xLeviNx]

This would be ideal to integrate. Nice work

[GLoOoccK]

@dvander