rustc_target: move in syntax::abi and flip dependency.

src/libsyntax/parse/parser.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use abi::{self, Abi};
+use rustc_target::spec::abi::{self, Abi};
 use ast::{AngleBracketedParameterData, ParenthesizedParameterData, AttrStyle, BareFnTy};
 use ast::{RegionTyParamBound, TraitTyParamBound, TraitBoundModifier};
 use ast::Unsafety;