Auto merge of #13387 - emilio:debug-assertions, r=aneeshusa,jdm,pcwalton

Honor SERVO_ENABLE_DEBUG_ASSERTIONS on the build machines.

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As part of #13127.

cc @aneeshusa

---
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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors

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components/style/properties/properties.mako.rs

@@ -1532,9 +1532,9 @@ impl ComputedValues {
     }
 
     #[inline]
-    pub fn logical_border_width(&self) -> LogicalMargin<Au> {
+    pub fn border_width_for_writing_mode(&self, writing_mode: WritingMode) -> LogicalMargin<Au> {
         let border_style = self.get_border();
-        LogicalMargin::from_physical(self.writing_mode, SideOffsets2D::new(
+        LogicalMargin::from_physical(writing_mode, SideOffsets2D::new(
             border_style.border_top_width,
             border_style.border_right_width,
             border_style.border_bottom_width,
@@ -1542,6 +1542,11 @@ impl ComputedValues {
         ))
     }
 
+    #[inline]
+    pub fn logical_border_width(&self) -> LogicalMargin<Au> {
+        self.border_width_for_writing_mode(self.writing_mode)
+    }
+
     #[inline]
     pub fn logical_margin(&self) -> LogicalMargin<computed::LengthOrPercentageOrAuto> {
         let margin_style = self.get_margin();