missed-spans: Fix bogus check.

I don't really know what it's trying to do, but forgetting about everything
you've seen before when you see whitespace followed by a semicolon doesn't look
right to me, and absolutely no tests were hitting that.

This check was introduced in 5ecdd072d6, however
it was wrong even at that point, and now rustfmt still passes that test,
regardless of macro name.

Fixes #3154.

src/missed_spans.rs

@@ -308,9 +308,6 @@ impl<'a> FmtVisitor<'a> {
                 status.line_start = i + 1;
             } else if c.is_whitespace() && status.last_wspace.is_none() {
                 status.last_wspace = Some(i);
-            } else if c == ';' && status.last_wspace.is_some() {
-                status.line_start = i;
-                status.last_wspace = None;
             } else {
                 status.last_wspace = None;
             }

tests/source/long-use-statement-issue-3154.rs

@@ -0,0 +1,3 @@
+// rustfmt-reorder_imports: false
+
+pub use self :: super :: super :: super :: root::mozilla::detail::StringClassFlags as nsTStringRepr_ClassFlags ;

tests/target/long-use-statement-issue-3154.rs

@@ -0,0 +1,3 @@
+// rustfmt-reorder_imports: false
+
+pub use self :: super :: super :: super :: root::mozilla::detail::StringClassFlags as nsTStringRepr_ClassFlags ;