Fix disassembly of indexed FMUL
Fix the decoding of the index used for the disassembly of FMUL on D-sized
registers, and add regression tests.
diff --git a/test/test-trace-reference/log-all b/test/test-trace-reference/log-all
index b61b90e..4037ec3 100644
--- a/test/test-trace-reference/log-all
+++ b/test/test-trace-reference/log-all
@@ -9843,7 +9843,7 @@
# v0: 0x00000000000000000000000000000000
0x~~~~~~~~~~~~~~~~ 6eb0f919 fminv s25, v8.4s
# v25: 0x0000000000000000000000007fc00000
-0x~~~~~~~~~~~~~~~~ 5fc91817 fmla d23, d0, v9.d[2]
+0x~~~~~~~~~~~~~~~~ 5fc91817 fmla d23, d0, v9.d[1]
# v23: 0x00000000000000000000000000000000
0x~~~~~~~~~~~~~~~~ 5f8711f7 fmla s23, s15, v7.s[0]
# v23: 0x00000000000000000000000000000000
@@ -9885,13 +9885,13 @@
# v28: 0x00000000000000000000000000000000
0x~~~~~~~~~~~~~~~~ 9eae0052 fmov x18, v2.D[1]
# x18: 0x0000000000000000
-0x~~~~~~~~~~~~~~~~ 5fc1988c fmul d12, d4, v1.d[2]
+0x~~~~~~~~~~~~~~~~ 5fc1988c fmul d12, d4, v1.d[1]
# v12: 0x00000000000000000000000000000000
0x~~~~~~~~~~~~~~~~ 5faf983e fmul s30, s1, v15.s[3]
# v30: 0x000000000000000000000000ffffffff
0x~~~~~~~~~~~~~~~~ 6e75dc19 fmul v25.2d, v0.2d, v21.2d
# v25: 0x00000000000000000000000000000000
-0x~~~~~~~~~~~~~~~~ 4fca9b0a fmul v10.2d, v24.2d, v10.d[2]
+0x~~~~~~~~~~~~~~~~ 4fca9b0a fmul v10.2d, v24.2d, v10.d[1]
# v10: 0x00000000000000000000000000000000
0x~~~~~~~~~~~~~~~~ 2e30df07 fmul v7.2s, v24.2s, v16.2s
# v7: 0x00000000000000000000000000000000
@@ -9901,7 +9901,7 @@
# v5: 0x00000000000000000000000000000000
0x~~~~~~~~~~~~~~~~ 4f88906b fmul v11.4s, v3.4s, v8.s[0]
# v11: 0x7fc000007fc000007fc000007fffffff
-0x~~~~~~~~~~~~~~~~ 7fc3993c fmulx d28, d9, v3.d[2]
+0x~~~~~~~~~~~~~~~~ 7fc3993c fmulx d28, d9, v3.d[1]
# v28: 0x00000000000000000000000000000000
0x~~~~~~~~~~~~~~~~ 7faf92b9 fmulx s25, s21, v15.s[1]
# v25: 0x00000000000000000000000000000000