swift234

Add SILValue::stripPointerProjections().

An address projection instruction is one of the following instructions:

1. struct_element_addr.
2. tuple_element_addr.
3. ref_element_addr.

This method takes in the given SILValue and continually searches up its
operand chain until it finds a non address projection, non-cast
value (where cast is defined as in SILValue::stripCasts()). The found
SILValue is then returned.

Swift SVN r12909