Most tests were using %swift or similar substitutions, which did not
include the target triple and SDK. The driver was defaulting to the
host OS. Thus, we could not run the tests when the standard library was
not built for OS X.
Swift SVN r24504
Give the ternary a fixed precedence, parse '?' and ':' into SequenceExprs, and fold them into IfExprs as part of sequence folding. This allows assignment operators like '+=' to have precedence below the ternary as in C. Fixes <rdar://problem/13756211>.
Swift SVN r4983
