i#143: presents the app's view of memory to the client wrt writable code
regions that DR has marked read-only.

Rather than trying to hide faults from the app, adds a flag
DR_MEMPROT_PRETEND_WRITE and puts the onus on the client to not write to
the region.

Added a test.

Does not fully fix i#143: we still need to adjust oldprot on
mprotect/ProtectVirtualMemory by the app.

git-svn-id: https://dynamorio.googlecode.com/svn/trunk@1925 49cc7528-f6fd-11dd-9d1a-b59b2e1864b6
i#1080: Fix special heap lock ranking

Documents a previously hidden constraint between exec_areas and module_data.

Fixes issue 1080.

Review URL: https://codereview.appspot.com/7384044

git-svn-id: https://dynamorio.googlecode.com/svn/trunk@1926 49cc7528-f6fd-11dd-9d1a-b59b2e1864b6