Support private constructors on nodes.

--HG--
extra : rebase_source : ac8c112308d9a8a4338fe8d4dfc44c6e272fa0fb
extra : __touch-noise__ : 2561517666
Use ArithmeticOpTable for primitive convert operations.

--HG--
extra : rebase_source : 9aa18391758f0902f45bd1c008602aa3a8859a5a
extra : __touch-noise__ : 1996028440
extra : amend_source : 1e8fc6337d0393acb834b3f69ce0dfe048d7babd
mx: follow redirects in URLConnectionDownload util

--HG--
extra : rebase_source : 7177d74958405e5b94b1ef004a0a57670c29b0f3
re-enabled use of Unsafe.allocateInstance based mechanism for Node cloning (based on JMH benchmarks)
re-added support for cloning a node without adding it to a graph
unittest: fix newline issue on windows

--HG--
extra : rebase_source : 31b3bf2fff3f1660a2248535d04cca4263ca5169
SL: use line separator of current platform

--HG--
extra : rebase_source : 612d33196dd8baa74486d522f1e47e9164eab691
DebugTimerTest: ignore on windows for now

--HG--
extra : rebase_source : 204c7abd456f238d6aac5c9af521fdb7bcdff04f
Re-add insertIntoGraph argument to Node.copyWithInputs method.

--HG--
extra : rebase_source : a7d257887a7f526f4b6ada4f955e108a6a440cbd
fixed reliability of DebugTimerTest
made selectability of using generated node functionality more fine grained
Merge.
better defaults for use of generated node functionality based on JMH benchmarks