nothrow new in cases where it maches intent

I wrote a hackish script to locate instances where new can throw
but where the original author has assumed that it will return
nullptr when there is a memory allocation problem.

In short, cases such as `ptr = new T; if (ptr) ...` has now
been changed to `ptr = new (std::nothrow) T; if (ptr) ...`.

Since a throwing `new` will always yield a non-nullptr pointer,
code that follows similar patterns to the previous example are
therefor redundant.

Example (from modules/access/dshow/filter.cpp):

    *ppEnum = new CaptureEnumMediaTypes( p_input, p_pin, this );

    if( *ppEnum == NULL )
      return E_OUTOFMEMORY; // unreachable, new will never return NULL

Fixed:

    *ppEnum = new (std::nothrow) CaptureEnumMediaTypes( p_input, p_pin, this );

    if( *ppEnum == NULL )
      return E_OUTOFMEMORY;

Signed-off-by: Hugo Beauzée-Luyssen <hugo@beauzee.fr>