[canvaskit] Make local-example explicitly use Python2
[canvaskit] Make local-example explicitly use Python2

The script doesn't work with Python3.

Change-Id: I9ea6397506500f76570540f78aa736873769f92b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/403016
Reviewed-by: Kevin Lubick <7cdab2cfab351f23814786ba39716e90eed69047@google.com>

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