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.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@273075 91177308-0d34-0410-b5e6-96231b3b80d8

src/experimental/filesystem/operations.cpp

@@ -669,7 +669,7 @@ void __resize_file(const path& p, std::uintmax_t size, std::error_code *ec) {
 
 space_info __space(const path& p, std::error_code *ec) {
     space_info si;
-    struct statvfs m_svfs;
+    struct statvfs m_svfs = {};
     if (::statvfs(p.c_str(), &m_svfs) == -1)  {
         set_or_throw(ec, "space", p);
         si.capacity = si.free = si.available =
@@ -678,7 +678,7 @@ space_info __space(const path& p, std::error_code *ec) {
     }
     if (ec) ec->clear();
     // Multiply with overflow checking.
-    auto do_mult = [&](std::uintmax_t& out, fsblkcnt_t other) {
+    auto do_mult = [&](std::uintmax_t& out, std::uintmax_t other) {
       out = other * m_svfs.f_frsize;
       if (out / other != m_svfs.f_frsize || other == 0)
           out = static_cast<std::uintmax_t>(-1);