reflect, runtime: add reflect support for regABI on loong64

reflect, runtime: add reflect support for regABI on loong64

Update #40724

Co-authored-by: Xiaolin Zhao <zhaoxiaolin@loongson.cn>
Change-Id: I0549fd1a2192ffb041034ff41bf0cc4be0b1662c
Reviewed-on: https://go-review.googlesource.com/c/go/+/521784
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Meidan Li <limeidan@loongson.cn>
Reviewed-by: David Chase <drchase@google.com>
Auto-Submit: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>