Port branches to ISLE (AArch64) (#4943)

* Port branches to ISLE (AArch64)

Ported the existing implementations of the following opcodes for AArch64
to ISLE:
- `Brz`
- `Brnz`
- `Brif`
- `Brff`
- `BrIcmp`
- `Jump`
- `BrTable`

Copyright (c) 2022 Arm Limited

* Remove dead code

Copyright (c) 2022 Arm Limited

cranelift/filetests/filetests/isa/aarch64/condbr.clif

@@ -290,8 +290,8 @@ block1:
 ;   cset x6, lo
 ;   subs xzr, x1, x3
 ;   cset x9, lt
-;   csel x6, x6, x9, eq
-;   subs xzr, xzr, x6
+;   csel x11, x6, x9, eq
+;   subs xzr, xzr, x11
 ;   b.lt label1 ; b label2
 ; block1:
 ;   b label3
@@ -314,8 +314,8 @@ block1:
 ;   cset x6, lo
 ;   subs xzr, x1, x3
 ;   cset x9, lo
-;   csel x6, x6, x9, eq
-;   subs xzr, xzr, x6
+;   csel x11, x6, x9, eq
+;   subs xzr, xzr, x11
 ;   b.lo label1 ; b label2
 ; block1:
 ;   b label3
@@ -338,9 +338,9 @@ block1:
 ;   cset x6, ls
 ;   subs xzr, x1, x3
 ;   cset x9, le
-;   csel x6, x6, x9, eq
-;   movz x9, #1
-;   subs xzr, x9, x6
+;   csel x11, x6, x9, eq
+;   movz w13, #1
+;   subs xzr, x13, x11
 ;   b.le label1 ; b label2
 ; block1:
 ;   b label3
@@ -363,9 +363,9 @@ block1:
 ;   cset x6, ls
 ;   subs xzr, x1, x3
 ;   cset x9, ls
-;   csel x6, x6, x9, eq
-;   movz x9, #1
-;   subs xzr, x9, x6
+;   csel x11, x6, x9, eq
+;   orr x13, xzr, #1
+;   subs xzr, x13, x11
 ;   b.ls label1 ; b label2
 ; block1:
 ;   b label3
@@ -388,8 +388,8 @@ block1:
 ;   cset x6, hi
 ;   subs xzr, x1, x3
 ;   cset x9, gt
-;   csel x6, x6, x9, eq
-;   subs xzr, x6, xzr
+;   csel x11, x6, x9, eq
+;   subs xzr, x11, xzr
 ;   b.gt label1 ; b label2
 ; block1:
 ;   b label3
@@ -412,8 +412,8 @@ block1:
 ;   cset x6, hi
 ;   subs xzr, x1, x3
 ;   cset x9, hi
-;   csel x6, x6, x9, eq
-;   subs xzr, x6, xzr
+;   csel x11, x6, x9, eq
+;   subs xzr, x11, xzr
 ;   b.hi label1 ; b label2
 ; block1:
 ;   b label3
@@ -436,9 +436,9 @@ block1:
 ;   cset x6, hs
 ;   subs xzr, x1, x3
 ;   cset x9, ge
-;   csel x6, x6, x9, eq
-;   movz x9, #1
-;   subs xzr, x6, x9
+;   csel x11, x6, x9, eq
+;   movz w13, #1
+;   subs xzr, x11, x13
 ;   b.ge label1 ; b label2
 ; block1:
 ;   b label3
@@ -461,9 +461,9 @@ block1:
 ;   cset x6, hs
 ;   subs xzr, x1, x3
 ;   cset x9, hs
-;   csel x6, x6, x9, eq
-;   movz x9, #1
-;   subs xzr, x6, x9
+;   csel x11, x6, x9, eq
+;   orr x13, xzr, #1
+;   subs xzr, x11, x13
 ;   b.hs label1 ; b label2
 ; block1:
 ;   b label3