Qt cannot be compiled from GIT when QT_NO_TOOLTIP is defined

Sometimes we need to compile Qt without tooltip support (for example in WASM, tooltip support seems to be broken). To turn off this feature QT_NO_TOOLTIP should be defined.

Using current Qt 5.13.1 version, if that is defined and the compilation is done from GIT repository, the "make install" fails since src/assistant/help/qhelpsearchquerywidget.cpp contains calls to ->setTooltip not guarded by checking for QT_NO_TOOLTIP.

Attached patches for Qt 5.13.1