Call to the runtime to generate escaping variables and use the returned
address when accessing these variables.

Fix a couple of errors on the way. The rule for CALLstatic was missed
during the Aux refactor and OCONVNOP wasn't converted.

Change-Id: I2096beff92cca92d648bfb6e8ec0b120f02f44af
Reviewed-on: https://go-review.googlesource.com/11072Reviewed-by: Keith Randall <khr@golang.org>