augment unaddr/uninit pattern match exceptions to ensure only final dword is allowed

_From [derek.br...@gmail.com](https://code.google.com/u/117968039472581148324/) on December 10, 2010 17:57:36_

PR 406718

xref PR 406535

this case covers adding more checks to the pattern matches for unaddressable and uninitialized exceptions
for string, memory, and alloca routines, to ensure that we're not letting through any true positives.
in particular, making sure only the end of a memory walk has errors suppressed, and not the middle.

xref is_ok_unaddressable_pattern(), check_undefined_reg_exceptions()

_Original issue: http://code.google.com/p/drmemory/issues/detail?id=102_