Fix mkdir_p in skpbench
Fix mkdir_p in skpbench

We were crashing when trying to write an image on android.

Bug: skia:
Change-Id: Id8a4e07ea2385838e122291530710e2e4e74dd8d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/205209
Reviewed-by: Robert Phillips <95e8ac5504948c7bf91b22c16a8dbb7ae7c66bfd@google.com>
Commit-Queue: Chris Dalton <ef7fc3a08ada7d31f16e9a18b5f3c728256e041e@google.com>

google/skia,rubenvb/skia,google/skia,rubenvb/skia,rubenvb/skia,aosp-mirror/platform_external_skia,google/skia,aosp-mirror/platform_external_skia,rubenvb/skia,google/skia,rubenvb/skia,HalCanary/skia-hc,HalCanary/skia-hc,google/skia,google/skia,rubenvb/skia,google/skia,HalCanary/skia-hc,google/skia,google/skia,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,google/skia,HalCanary/skia-hc,HalCanary/skia-hc,aosp-mirror/platform_external_skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,rubenvb/skia,HalCanary/skia-hc,aosp-mirror/platform_external_skia,aosp-mirror/platform_external_skia,HalCanary/skia-hc,HalCanary/skia-hc,aosp-mirror/platform_external_skia,rubenvb/skia,rubenvb/skia,rubenvb/skia