Since the intention of using AllStatic class is to provide classes that
only contain static method functions without member variables so it
doesn't have to be instantiated at all.

However, current implementation only disables dynamic instantiation, and
it can be detected at runtime by reaching UNREACHABLE().  And it can
still have instances allocated inside stack.

This blocks all those cases by deleting default constructor of AllStatic
class to prevent undesirable usage of it.

BUG=
R=jochen@chromium.org

Review-Url: https://codereview.chromium.org/2108273003
Cr-Commit-Position: refs/heads/master@{#37532}