Make Bazelisk's cache writable when using sandboxing. (#497)
Make Bazelisk's cache writable when using sandboxing. (#497)

Runing Bazelisk from within an integration test on Linux or MacOS would
fail if sandboxing was enabled since Bazelisk wasn't allowed to write to
its cache directory.

This commit adds a test flag that fixes this problem. No action is
needed on Windows since there is no sandboxing.
bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration