Fix TimeValue::now() on Unix.

TimeValue()::now().toEpochTime() is supposed to be the same as time(),
but it wasn't, because toEpoch subtracted PosixZeroTime, but now()
didn't add PosixZeroTime!
Add a unittest to check this works.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94178 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/System/Unix/TimeValue.inc b/lib/System/Unix/TimeValue.inc
index 1ae8c71..d8cc8f5 100644
--- a/lib/System/Unix/TimeValue.inc
+++ b/lib/System/Unix/TimeValue.inc
@@ -48,7 +48,7 @@
   }
 
   return TimeValue(
-    static_cast<TimeValue::SecondsType>( the_time.tv_sec ), 
+    static_cast<TimeValue::SecondsType>( the_time.tv_sec + PosixZeroTime.seconds_ ), 
     static_cast<TimeValue::NanoSecondsType>( the_time.tv_usec * 
       NANOSECONDS_PER_MICROSECOND ) );
 }