and its test.
Minidump context structures now interoperate more easily with snapshot
CPUContext structures, while maintaining identical layout to before.
This is facilitated by reusing the Fxsave types for the substructures
which were completely identical, and by using compatible logic to
initialize the minidump and snapshot structures for testing.
TEST=minidump_test, snapshot_test
R=rsesek@chromium.org
Review URL: https://codereview.chromium.org/686353004