Request for reviews (S): 6959430: Make sure raw loads have control edge

[Vladimir Kozlov]

I will push it after 6953058 fix is pulled into our repository.

http://cr.openjdk.java.net/~kvn/6959430/webrev

Fixed 6959430: Make sure raw loads have control edge

Safepoint polls don't produce a new raw memory state
so loads of raw are allowed to float above safepoint
during which a raw value could be modified.

Note, I added two checks. One is in factory methods
so the call stack will show where it is called from.
An other is in final graph reshape code to catch
nodes for which constructors were used directly.

Passed CTW and JPRT.