freedreno/ir3: Allow high registers in sources

I have no idea if these are allowed in destinations, but they are
allowed to be propagated by copy propagation, so codify the current
de-facto rules by allowing them on sources. If it turns out that some
sources don't handle these, or that some additional sources do allow
them on a6xx, then we can rework it later. This fixes "INVALID FLAGS"
spam with compute shaders in debug mode.
38 jobs for !3622 with ir3-high-regs in 48 minutes and 49 seconds (queued for 5 seconds)
latest detached
Status Job ID Name Coverage
  Container
passed #1494336
aarch64
arm_build

00:00:19

passed #1494337
aarch64
arm_test

00:00:30

passed #1494333
x86_build

00:00:20

passed #1494335
x86_build_old

00:00:21

passed #1494334
x86_test-gl

00:00:21

 
  Build
passed #1494341
aarch64
meson-arm64

00:11:17

passed #1494340
aarch64
meson-armhf

00:08:04

passed #1494342
meson-clang

00:09:51

passed #1494345
meson-clover

00:05:02

passed #1494346
meson-clover-old-llvm

00:06:49

passed #1494348
meson-i386

00:03:21

passed #1494339
meson-main

00:07:05

passed #1494349
meson-mingw32-x86_64

00:05:12

passed #1494338
meson-testing

00:05:29

passed #1494347
meson-vulkan

00:02:22

passed #1494350
scons

00:05:35

passed #1494351
scons-old-llvm

00:03:34

passed #1494343
scons-swr

00:08:45

passed #1494344
scons-win64

00:05:22

 
  Test
passed #1494370
db410c
arm64_a306_gles2

00:06:16

passed #1494367
mesa-cheza
arm64_a630_gles2

00:03:59

passed #1494369
mesa-cheza
arm64_a630_gles3

00:07:02

passed #1494368
mesa-cheza
arm64_a630_gles31

00:04:42

passed #1494355
lava-meson-gxl-s905x-libretech-cc
lima-mali450-test:arm64

00:08:56

passed #1494352
lava-sun50i-h6-pine-h64
panfrost-t720-test:arm64

00:08:40

passed #1494353
lava-rk3288-veyron-jaq
panfrost-t760-test:armhf

00:05:41

passed #1494354
lava-rk3399-gru-kevin
panfrost-t860-test:arm64

00:07:13

passed #1494357
piglit-glslparser

00:03:22

passed #1494356
piglit-quick_gl

00:09:33

passed #1494358
piglit-quick_shader

00:04:28

passed #1494359
test-llvmpipe-gles2

00:02:47

passed #1494360
test-softpipe-gles2

00:02:14

passed #1494363
test-softpipe-gles31 1/4

00:02:05

passed #1494361
test-softpipe-gles3 1/2

00:05:34

passed #1494364
test-softpipe-gles31 2/4

00:04:01

passed #1494365
test-softpipe-gles31 3/4

00:03:47

passed #1494366
test-softpipe-gles31 4/4

00:03:18

passed #1494362
test-softpipe-gles3 2/2

00:06:25