FULLPIPE: Map screen, array OOB access

[bgK]

ScummVM: 64c88d4c4fd069dae321cc576259ef88a7cb2b78
Game: German full version

Steps to reproduce:

• From the beginning of the game, enter the left pipe to the room with the creatures playing dominoes
• Click on '2' on the elevator control panel
• While the elevator is moving up, open the map

scummvm: ../common/array.h:192: T& Common::Array<T>::operator[](Common::Array<T>::size_type) [with T = Fullpipe::BigPicture*; Common::Array<T>::size_type = unsigned int]: Assertion `idx < _size' failed.
(gdb) bt full
#3  0x00007ffff40e3153 in __assert_fail () from /usr/lib/libc.so.6
#4  0x00005555556bd6b6 in Common::Array<Fullpipe::BigPicture*>::operator[] (this=0x611000586068, idx=3) at ../common/array.h:192
        __PRETTY_FUNCTION__ = "T& Common::Array<T>::operator[](Common::Array<T>::size_type) [with T = Fullpipe::BigPicture*; Common::Array<T>::size_type = unsigned int]"
#5  0x00005555556dbf51 in Fullpipe::Background::getBigPicture (this=0x611000586000, x=0, y=1) at ../engines/fullpipe/gfx.h:217
#6  0x0000555555757671 in Fullpipe::Scene::drawContent (this=0x611000586000, minPri=60000, maxPri=0, drawBg=true)
    at ../engines/fullpipe/scene.cpp:722
        v27 = 0x7fff05050640
        y = 600
        v25 = 1
        oldx = 800
        bgStX = 306
        bgNumX = 0
        bgOffsetX = 306
        bgStY = 684
        bgNumY = 1
        bgOffsetY = 84
        bgPosX = 0
        width = 1600
        height = 600
        dims = {x = 1600, y = 1285}
#7  0x000055555575544d in Fullpipe::Scene::draw (this=0x611000586000) at ../engines/fullpipe/scene.cpp:511
        priority = -18320
#8  0x0000555555700228 in Fullpipe::ModalMap::update (this=0x60b00019f860) at ../engines/fullpipe/modal.cpp:587
#9  0x000055555569a859 in Fullpipe::FullpipeEngine::updateScreen (this=0x61e000020480) at ../engines/fullpipe/fullpipe.cpp:485
#10 0x0000555555698201 in Fullpipe::FullpipeEngine::run (this=0x61e000020480) at ../engines/fullpipe/fullpipe.cpp:303
        time2 = 244362
        format = {bytesPerPixel = 4 '\004', rLoss = 0 '\000', gLoss = 0 '\000', bLoss = 0 '\000', aLoss = 0 '\000', rShift = 24 '\030', 
          gShift = 16 '\020', bShift = 8 '\b', aShift = 0 '\000'}
        scene = 0
        time1 = 244362

[bgK]

Fixed in 694990e712598f