[AArch64][FPenv] Update chain of int to fp conversion
When using strict fp, it is required to update the
chain when performing integer type promotion of a
operand to a integer to floating point conversion.
Reviewers: craig.topper, john.brawn
Reviewed By: craig.topper
Subscribers: kristof.beyls, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D74597