cmd/asm: initialize assembler before running error tests
The Test{ARCH}Errors tests will call ctxt.Arch.Assemble, but this
function requires the assembler has been initialized. So this CL adds
a call to architecture.Init(ctxt) in testErrors, otherwise running
Test{ARCH}Errors alone would fail.
Change-Id: I4f3ba5a5fc1375d28779701989cf700cb4d1b635
Reviewed-on: https://go-review.googlesource.com/c/go/+/505976 Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Eric Fang <eric.fang@arm.com>