tdf#142839: do not forget to initialize *pHeightNTP

Regression after commit d0a1616ccad0dd5f5a02c1b0204f537b57d0b4b5

Change-Id: Iaa8f67e0c7e3d99b057294717d24ffac4ad3534c
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/117389
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>
diff --git a/editeng/source/editeng/impedit2.cxx b/editeng/source/editeng/impedit2.cxx
index 14685e7..4bc8a570 100644
--- a/editeng/source/editeng/impedit2.cxx
+++ b/editeng/source/editeng/impedit2.cxx
@@ -3410,6 +3410,8 @@ sal_uInt32 ImpEditEngine::GetTextHeightNTP() const
tools::Long ImpEditEngine::Calc1ColumnTextHeight(tools::Long* pHeightNTP)
{
    tools::Long nHeight = 0;
    if (pHeightNTP)
        *pHeightNTP = 0;
    // Pretend that we have ~infinite height to get total height
    comphelper::ValueRestorationGuard aGuard(nCurTextHeight,
                                             std::numeric_limits<tools::Long>::max());
@@ -3440,6 +3442,8 @@ tools::Long ImpEditEngine::CalcTextHeight(tools::Long* pHeightNTP)
    tools::Long nTentativeColHeight = mnMinColumnWrapHeight;
    tools::Long nWantedIncrease = 0;
    tools::Long nCurrentTextHeight;
    if (pHeightNTP)
        *pHeightNTP = 0;

    // This does the necessary column balancing for the case when the text does not fit min height.
    // When the height of column (taken from nCurTextHeight) is too small, the last column will