swift234

IRGen: Don't lazily emit witness tables.

With runtime conformance lookup, it isn't possible without more complex analysis to determine whether a witness table is needed at runtime. In particular, in whole-module mode, it looked like no protocol conformances in the test/Interpreter/protocol_lookup.swift test were used, causing all of the tests to fail in -i mode. Erik's been working on SIL-level dead witness elimination which will hopefully offset the compile time hit here.

Swift SVN r23067