Add additional tests in an attempt to diagnose ARM test failures.

Currently 4 tests are failing on the ARM buildbot. To try and diagnose each
of the failures this patch does the following:

1) path.itr/iterator.pass.cpp
   * Temporarily print iteration sequence to see where its failing.

2) path.native.obs/string_alloc.pass.cpp
   * Remove test that ::new is not called when constructing a short string
     that requires a conversion. Since during the conversion global locale
     objects might be constructed.

3) fs.op.funcs/space.pass.cpp
   * Explicitly use uintmax_t in the implementation of space, hopefully
     preventing possible overflows.
   * Add additional tests that check for overflow is the calculation of the
     space_info values.
   * Add additional tests for the values returned from statfvs.

4) fs.op.funcs/last_write_time.pass.cpp
   * No changes made yet.

llvm-svn: 273075