cmd/compile/internal: intrinsify publicationBarrier on loong64

cmd/compile/internal: intrinsify publicationBarrier on loong64

The publication barrier is a StoreStore barrier, which is implemented
by "DBAR 0x1A" [1] on loong64.

goos: linux
goarch: loong64
pkg: runtime
cpu: Loongson-3A6000 @ 2500.00MHz
                     |   bench.old   |  bench.new                            |
                     |    sec/op     |   sec/op        vs base               |
Malloc8                 31.76n ± 0%     22.79n ± 0%   -28.24% (p=0.000 n=20)
Malloc8-2               25.46n ± 0%     18.33n ± 0%   -28.00% (p=0.000 n=20)
Malloc8-4               25.75n ± 0%     18.43n ± 0%   -28.41% (p=0.000 n=20)
Malloc16                62.97n ± 0%     42.41n ± 0%   -32.65% (p=0.000 n=20)
Malloc16-2              49.11n ± 0%     31.68n ± 0%   -35.50% (p=0.000 n=20)
Malloc16-4              49.64n ± 1%     31.95n ± 0%   -35.62% (p=0.000 n=20)
MallocTypeInfo8         58.57n ± 0%     46.51n ± 0%   -20.61% (p=0.000 n=20)
MallocTypeInfo8-2       51.43n ± 0%     38.01n ± 0%   -26.09% (p=0.000 n=20)
MallocTypeInfo8-4       51.65n ± 0%     38.15n ± 0%   -26.13% (p=0.000 n=20)
MallocTypeInfo16        68.07n ± 0%     51.62n ± 0%   -24.17% (p=0.000 n=20)
MallocTypeInfo16-2      54.73n ± 0%     41.13n ± 0%   -24.85% (p=0.000 n=20)
MallocTypeInfo16-4      55.05n ± 0%     41.28n ± 0%   -25.02% (p=0.000 n=20)
MallocLargeStruct       491.5n ± 0%     454.8n ± 0%    -7.47% (p=0.000 n=20)
MallocLargeStruct-2     351.8n ± 1%     323.8n ± 0%    -7.94% (p=0.000 n=20)
MallocLargeStruct-4     333.6n ± 0%     316.7n ± 0%    -5.10% (p=0.000 n=20)
geomean                 71.01n          53.78n        -24.26%

[1]: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html

Change-Id: Ica0c89db6f2bebd55d9b3207a1c462a9454e9268
Reviewed-on: https://go-review.googlesource.com/c/go/+/577515
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: sophie zhao <zhaoxiaolin@loongson.cn>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Qiqi Huang <huangqiqi@loongson.cn>
Reviewed-by: Meidan Li <limeidan@loongson.cn>
Reviewed-by: Carlos Amedee <carlos@golang.org>