RFR(XS): 8219611: Remove superfluous sigfillset code

[Mikael Vidstedt]

Please review this change which removes some superfluous code.

Bug: https://bugs.openjdk.java.net/browse/JDK-8219611 <https://bugs.openjdk.java.net/browse/JDK-8219611>
webrev: http://cr.openjdk.java.net/~mikael/webrevs/8219611/webrev.00/open/webrev/ <http://cr.openjdk.java.net/~mikael/webrevs/8219611/webrev.00/open/webrev/>

From JBS:

As part of https://bugs.openjdk.java.net/browse/JDK-8190308 the following code was added to os_posix.cpp (in os::create_file_for_heap): 

48153: sigset_t set, oldset; 
48153: int ret = sigfillset(&set); 
48153: assert_with_errno(ret == 0, "sigfillset returned error"); 

The "set" and "oldset" variables are not used later in the function, and sigfillset only affects the "set" variable, so this code is effectively a no-op.

Cheers,
Mikael