[fuchsia] Replace system-temp with isolated-temp.
[fuchsia] Replace system-temp with isolated-temp.

This change replaces system-temp with isolated-temp. As system-temp is
now deprecated.

Bug: fuchsia:25081
Change-Id: I4f87b69caa95df7c9809c3eb3d0f7e40ef4cddad
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/266974
Reviewed-by: John Rosasco <14868e44194333765c84ed78486aa6809fc4e8f1@google.com>
Auto-Submit: Benjamin Wright <d97cb5a683a42395ddbd3524ae4315b2c4b93d14@google.com>
Commit-Queue: Mike Klein <14574f09dfa9b4e14759b88c3426a495a0e627b0@google.com>

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