Backed out 2 changesets (bug 1572211) for mochitests failures on test_stack-parameters.html on a CLOSED TREE

Backed out changeset 48fa8b517d7b (bug 1572211)
Backed out changeset a5d589b74745 (bug 1572211)

layout/mathml/nsMathMLmfracFrame.cpp

@@ -316,6 +316,10 @@ nsresult nsMathMLmfracFrame::PlaceInternal(DrawTarget* aDrawTarget,
                          : gfxMathTable::StackGapMin,
             oneDevPixel);
       }
+      // Factor in axis height
+      // http://www.mathml-association.org/MathMLinHTML5/S3.html#SS3.SSS2
+      numShift += axisHeight;
+      denShift += axisHeight;
 
       nscoord actualClearance =
           (numShift - bmNum.descent) - (bmDen.ascent - denShift);

testing/web-platform/meta/mathml/presentation-markup/fractions/frac-parameters-2.html.ini

@@ -0,0 +1,13 @@
+[frac-parameters-2.html]
+  [TopDisplayStyleShiftUp]
+    expected: FAIL
+
+  [BottomDisplayStyleShiftDown]
+    expected: FAIL
+
+  [BottomShiftDown]
+    expected: FAIL
+
+  [ToShiftUp]
+    expected: FAIL
+