i#387: Mark TestMemProtChg flaky on Linux.
i#387: Mark TestMemProtChg flaky on Linux.

There still seem to be some stack protection corner cases in
/proc/pid/maps that we can't puzzle out.

Review URL: https://codereview.appspot.com/6441071

git-svn-id: ed337ca7cdb08c0ba29d8fe58632bb7686892c2d@1499 49cc7528-f6fd-11dd-9d1a-b59b2e1864b6

rnk/dynamorio,rnk/dynamorio,rnk/dynamorio,rnk/dynamorio,rnk/dynamorio