support NDK r22 beta
support NDK r22 beta

I was curious to try r22 out today and it needed these small tweaks,
which should be compatible with r21d.  I'll hold off on the actual
upgrade until r22 is out of beta.

Builds using the NDK compilers (r21d or r22 both) don't even need the
remaining --sysroot flag, but keeping it lets GOMA builds using Chrome's
compilers keep working.

Change-Id: Ic30cb9e00fe91179ca219999a9f3131ace61f753
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/334396
Reviewed-by: Leon Scroggins <995cad867ca30d6399abe011583a53547c8afea1@google.com>
Commit-Queue: Mike Klein <14574f09dfa9b4e14759b88c3426a495a0e627b0@google.com>

google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,google/skia,google/skia,google/skia,google/skia,google/skia