libstdc++ remote host testing fix

[Paolo Carlini]

Joseph S. Myers wrote:
> This patch fixes problems with remote-host libstdc++ testing.  In the
> remote-host case, libstdc++_init copies headers under util/ to the
> remote host, but it was missing .h and .tcc files under
> regression/rand/*, so causing some testcases relying on those headers
> to fail.  This patch expands the globs in question to cover all the
> suffixes used at all the directory levels used (rather than limiting
> it to suffixes used at a particular level and so requiring changes if
> a header with an existing suffix is added at a new level); it removes
> a duplicate reference to "${srcdir}/util/*/*.hpp" in the process.  OK
> to commit?
>   
Sure, thanks a lot!

Paolo.