Replace target.target with target and target.ptr_width with target.pointer_width

Preparation for a subsequent change that replaces
rustc_target::config::Config with its wrapped Target.

On its own, this commit breaks the build. I don't like making
build-breaking commits, but in this instance I believe that it
makes review easier, as the "real" changes of this PR can be
seen much more easily.

Result of running:

find compiler/ -type f -exec sed -i -e 's/target\.target\([)\.,; ]\)/target\1/g' {} \;
find compiler/ -type f -exec sed -i -e 's/target\.target$/target/g' {} \;
find compiler/ -type f -exec sed -i -e 's/target.ptr_width/target.pointer_width/g' {} \;
./x.py fmt

compiler/rustc_codegen_llvm/src/declare.rs

@@ -42,7 +42,7 @@ fn declare_raw_fn(
     // be merged.
     llvm::SetUnnamedAddress(llfn, llvm::UnnamedAddr::Global);
 
-    if cx.tcx.sess.opts.cg.no_redzone.unwrap_or(cx.tcx.sess.target.target.options.disable_redzone) {
+    if cx.tcx.sess.opts.cg.no_redzone.unwrap_or(cx.tcx.sess.target.options.disable_redzone) {
         llvm::Attribute::NoRedZone.apply_llfn(Function, llfn);
     }