related tdf#157572 docx export framePr: no w:x if zero or xAlign

xAlign has none of the complexities of yAlign.
if xAlign is defined, it takes priority over w:x.
So simply don't write out an unnecessary w:x
if it is the default value (0) or if there is a xAlign.

This change is just made to keep the code somewhat consistent
between w:x and w:y.

Change-Id: I5ef1da309e35e25660247675ba9ab6e336becd41
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/157566
Tested-by: Jenkins
Reviewed-by: Justin Luth <jluth@mail.com>
diff --git a/sw/source/filter/ww8/docxattributeoutput.cxx b/sw/source/filter/ww8/docxattributeoutput.cxx
index 1444698..4f0c67f 100644
--- a/sw/source/filter/ww8/docxattributeoutput.cxx
+++ b/sw/source/filter/ww8/docxattributeoutput.cxx
@@ -1049,14 +1049,14 @@ void DocxAttributeOutput::PopulateFrameProperties(const SwFrameFormat* pFrameFor
    attrList->add( FSNS( XML_w, XML_w), OString::number(nAdjustedWidth));
    attrList->add( FSNS( XML_w, XML_h), OString::number(rSize.Height()));

    attrList->add( FSNS( XML_w, XML_x), OString::number(aPos.X));

    const OString relativeFromH = convertToOOXMLHoriOrientRel(rHoriOrient.GetRelationOrient());
    const OString relativeFromV = convertToOOXMLVertOrientRel(rVertOrient.GetRelationOrient());
    OString aXAlign = convertToOOXMLHoriOrient(rHoriOrient.GetHoriOrient(), /*bIsPosToggle=*/false);
    OString aYAlign = convertToOOXMLVertOrient(rVertOrient.GetVertOrient());
    if (!aXAlign.isEmpty())
        attrList->add(FSNS(XML_w, XML_xAlign), aXAlign);
    else if (aPos.X)
        attrList->add( FSNS( XML_w, XML_x), OString::number(aPos.X));
    if (!aYAlign.isEmpty() && relativeFromV != "text")
        attrList->add(FSNS(XML_w, XML_yAlign), aYAlign);
    else if (aPos.Y)