tcg/aarch64: Emit BTI insns at jump landing pads

tcg/aarch64: Emit BTI insns at jump landing pads

The prologue is entered via "call"; the epilogue, each tb,
and each goto_tb continuation point are all reached via "jump".

As tcg_out_goto_long is only used by tcg_out_exit_tb, merge
the two functions.  Change the indirect register used to
TCG_REG_TMP1, aka X17, so that the BTI condition created
is "jump" instead of "jump or call".

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>