Format libstd/sys with rustfmt

This commit applies rustfmt with rust-lang/rust's default settings to
files in src/libstd/sys *that are not involved in any currently open PR*
to minimize merge conflicts. THe list of files involved in open PRs was
determined by querying GitHub's GraphQL API with this script:
https://gist.github.com/dtolnay/aa9c34993dc051a4f344d1b10e4487e8

With the list of files from the script in outstanding_files, the
relevant commands were:

    $ find src/libstd/sys -name '*.rs' \
        | xargs rustfmt --edition=2018 --unstable-features --skip-children
    $ rg libstd/sys outstanding_files | xargs git checkout --

Repeating this process several months apart should get us coverage of
most of the rest of the files.

To confirm no funny business:

    $ git checkout $THIS_COMMIT^
    $ git show --pretty= --name-only $THIS_COMMIT \
        | xargs rustfmt --edition=2018 --unstable-features --skip-children
    $ git diff $THIS_COMMIT  # there should be no difference

1 files changed, 1 insertions, 5 deletions

diff --git a/src/libstd/sys/hermit/alloc.rs b/src/libstd/sys/hermit/alloc.rs
index 86cc4463632..d153914e77e 100644
--- a/src/libstd/sys/hermit/alloc.rs
+++ b/src/libstd/sys/hermit/alloc.rs
@@ -13,11 +13,7 @@ unsafe impl GlobalAlloc for System {
         let addr = abi::malloc(layout.size(), layout.align());
 
         if !addr.is_null() {
-            ptr::write_bytes(
-                addr,
-                0x00,
-                layout.size()
-            );
+            ptr::write_bytes(addr, 0x00, layout.size());
         }
 
         addr