[OpenMP][AArch64] Fix frame pointer save in microtask (#165313) When OMPT is enabled, the stack pointer was not saved to frame pointer register immediately after storing the frame pointer to the stack. Therefore the frame pointers did not constitute a proper chain. Fixes [#163352](https://github.com/llvm/llvm-project/issues/163352) GitOrigin-RevId: 77c1db47efb3cbc37b59b4be8eaa9ebaecedf360