Otherwise we can get in trouble when a local type is named, say,
'Sequence'.
Also contains test updates and a fix for Harlan's previous commit,
which actually affects all typealiases, not just those in the Builtin
module.
Since this text is only needed for printing a parseable interface during
a non-whole-module build, only put the text inside partial modules. When
we're merging the modules at the end, skip serializing the text.
rdar://44394186
Commit to a command line option spelling so that build systems can
start testing it. I deliberately picked one of the longer names we
were considering because we can always decide to add a shorter alias,
but can't decide a shorter name was too generic.
Like the other supplementary output flags,
-emit-parseable-module-interface-path will emit a .swiftinterface file
to a particular path, while -emit-parseable-module-interface will put
it next to the main output (the one specified with -o).
rdar://problem/43776945
We already have something called "module interfaces" -- it's the
generated interface view that you can see in Xcode, the interface
that's meant for developers using a library. Of course, that's also a
textual format. To reduce confusion, rename the new module stability
feature to "parseable [module] interfaces".
