Update to 1.61.0 in fbcode and xplat (2nd attempt)

Summary:
This diff consists of `hg backout D37023453 (https://github.com/facebookincubator/gazebo_lint/commit/63bb3ebe9b297130c8277dbd543989d2652cf51e)` ({D37023453 (63bb3eb)}) + `tp2_update_fbcode rust` to pick up {D37030185}.

See summary of D37030185 for a description of the regression in the first 1.61.0 upgrade. In brief, rustc switching from `num_cpus` to `available_parallelism` resulted in misidentifying the number of available CPUs in some environments including Remote Execution, resulting in enormously increased memory usage and failing builds. I simply reverted that to go back to `num_cpus`, same as what was used in all prior Rust versions.

Reviewed By: zertosh, diliop

Differential Revision: D37036063

fbshipit-source-id: 9520b93b07620fbb35ab7902b8975be9ac329a11

Author: David Tolnay

gazebo_lint/src/clippy.rs

@@ -190,11 +190,11 @@ pub fn match_def_path(cx: &LateContext, did: DefId, syms: &[&str]) -> bool {
 /// Matches the given `ty` with generics to the given types and generic types
 pub fn match_ty_path(cx: &LateContext, ty: Ty, ty_path: &[&str], generic_tys: &[&[&str]]) -> bool {
     if let TyKind::Adt(ty, subst) = ty.kind() {
-        if match_def_path(cx, ty.did, ty_path) {
+        if match_def_path(cx, ty.did(), ty_path) {
             let mut i = 0;
             while i < generic_tys.len() {
                 if let Some(ty_param) = subst.type_at(i).ty_adt_def() {
-                    if !match_def_path(cx, ty_param.did, generic_tys[i]) {
+                    if !match_def_path(cx, ty_param.did(), generic_tys[i]) {
                         return false;
                     } else {
                         i += 1;

gazebo_lint/src/lib.rs

@@ -428,7 +428,7 @@ fn check_impl_dupe(cx: &LateContext, item: &Item) {
     ) -> bool {
         match self_tys.kind() {
             TyKind::Adt(self_adt, sub) => {
-                for variant in self_adt.variants.iter() {
+                for variant in self_adt.variants() {
                     let mut fields = variant.fields.iter();
                     if let Some(field) = fields.next() {
                         if fields.next().is_some() {