Revert "fuchsia: Include reference to zx library"

This reverts commit de5bc33b8b45b197977430a0e74a37c00c6a3bc3.

Reason for revert: going to be removed back out of the SDK, transitions are hard :( https://bugs.fuchsia.dev/p/fuchsia/issues/detail?id=7802#c33

Original change's description:
> fuchsia: Include reference to zx library
> 
> "library zx" used to be built in to fidlc, but is now a standalone file
> (this is an SDK change). Update the build rules to adapt to this.
> 
> ref: https://logs.chromium.org/logs/crashpad/buildbucket/cr-buildbucket.appspot.com/8883567878548782112/+/steps/compile_with_ninja/0/stdout
> 
> FAILED: gen/fidl/include/fuchsia/sysinfo/c/client.cc gen/fidl/include/fuchsia/sysinfo/c/fidl.h gen/third_party/fuchsia/fidl/fuchsia.sysinfo/tables.c gen/third_party/fuchsia/fidl/fuchsia.sysinfo/intermediary_representation.json
> python ../../third_party/fuchsia/runner.py ../../third_party/fuchsia/sdk/linux-amd64/tools/fidlc --c-header gen/fidl/include/fuchsia/sysinfo/c/fidl.h --c-client gen/fidl/include/fuchsia/sysinfo/c/client.cc --tables gen/third_party/fuchsia/fidl/fuchsia.sysinfo/tables.c --json gen/third_party/fuchsia/fidl/fuchsia.sysinfo/intermediary_representation.json --name fuchsia.sysinfo --files ../../third_party/fuchsia/sdk/linux-amd64/fidl/fuchsia.sysinfo/sysinfo.fidl
> ../../third_party/fuchsia/sdk/linux-amd64/fidl/fuchsia.sysinfo/sysinfo.fidl:7:7: error: Could not find library named zx. Did you include its sources with --files?
> using zx;
>       ^~
> 
> Bug: fuchsia:7802
> Change-Id: I10c0109fd9621a19d72deb21a489c2041caeeeca
> Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/2141019
> Commit-Queue: Scott Graham <scottmg@chromium.org>
> Commit-Queue: Justin Cohen <justincohen@chromium.org>
> Reviewed-by: Justin Cohen <justincohen@chromium.org>

TBR=justincohen@chromium.org,scottmg@chromium.org

Change-Id: I0328c2ff586ff733926a51d87774453cb2cf7c33
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: fuchsia:7802
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/2143940
Reviewed-by: Scott Graham <scottmg@chromium.org>
Commit-Queue: Scott Graham <scottmg@chromium.org>

third_party/fuchsia/BUILD.gn

@@ -156,8 +156,6 @@ if (crashpad_is_in_fuchsia) {
         "--name",
         fidl_source.library_name,
         "--files",
-        rebase_path("$sdk_fidl_sources_path/zx/zx_common.fidl", root_build_dir),
-        "--files",
         rebase_path(fidl_source.fidl, root_build_dir),
       ]