Clean include directory paths

To remove '../' and other strangeness from compiler arguments, which run
into problems with remote execution:

  Android.mk: LOCAL_C_INCLUDES := $(LOCAL_PATH)/include/bar/..
  foo.c: #include "foo.h"
  include/foo.h

In this case, we'll send foo.c and include/foo.h, but include/bar may be
empty, and not exist on the remote server. So while the file is there,
you may not be able to access it.

There's also a byproduct of removing extra '/' and './' components,
which should be harmless.

Fixes: 144109314
Test: diff build-aosp_arm.ninja before/after; scan diffs
Test: treehugger
Change-Id: Id2eceba76fbf9b1524487e82cb5c8903c815e45f