swift234

REPL: Create a new MemoryBuffer for each input.

Instead of reusing a fixed-size buffer, which causes problems when error messages refer back to previous inputs and corrupts AST references in *LiteralExpr that point back into source buffers, allocate each REPL input into its own buffer with its own SourceMgr entry. Fixes <rdar://problem/13387167>, crashes when using :dump_ast on expressions containing integer/float literal expr nodes, and hopefully sporadic buildbot failures running the Interpreter/repl test.

Swift SVN r5470