qt5: bump latest version to 5.9.4

qt5: bump latest version to 5.9.4

qt5connectivity:
 - removed
 0001-Example-heartrate-server-needs-only-core-and-bluetoo.patch
 (upstream comitted [1])

qt5quickcontrols2:
 - removed 0001-Example-flatstyle-needs-widgets-module.patch (upstream
 comitted [2])

qt5webengine:
 - removed 0002-Load-libEGL-and-libGLES2-symbols-implicitly.patch
 (upstream comitted, reverted and recomitted [3])

[1] https://codereview.qt-project.org/211810
[2] https://codereview.qt-project.org/212583
[3] https://codereview.qt-project.org/209547

Signed-off-by: Sébastien Szymanski <sebastien.szymanski@armadeus.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>