Fix core.gni to use not use Assembler for none cpu.
Right now, there are no outputs because we aren't compiling
dm or nanobench. However, this still compiles the skia
library and creates two executables, so it's a good canary
for a real WASM build.
Additional note: the two executables in question don't draw
anything to the screen via GL, which is still not possible with
Skia+WASM.
Bug: skia:
Change-Id: I0d767467e94e40d01070e34223dd90e96f1c96f2
Reviewed-on: https://skia-review.googlesource.com/49540
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
Reviewed-by: Eric Boren <borenet@google.com>
