Bug 407550

SUMMARY
Hi,
KWin crashes (but restart then) when I switch desktop while closing a window with the destroy effect.

STEPS TO REPRODUCE
1. Enable destroy windows effect
2. Open a window, such as terminal
3. Close it, then switch desktop while animation is playing

OBSERVED RESULT
The desktop will freeze a little time, then kwin will restart. 




EXPECTED RESULT


SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: Linux 5.0.13-arch1-1-ARCH
(available in About System)
KDE Plasma Version: 5.15.5-1
KDE Frameworks Version: 5.57.0
Qt Version: 5.12.3

ADDITIONAL INFORMATION

Here is my lscpu
```
Architecture:        x86_64
CPU op-mode(s):      32-bit, 64-bit
Byte Order:          Little Endian
Address sizes:       39 bits physical, 48 bits virtual
CPU(s):              4
On-line CPU(s) list: 0-3
Thread(s) per core:  1
Core(s) per socket:  4
Socket(s):           1
NUMA node(s):        1
Vendor ID:           GenuineIntel
CPU family:          6
Model:               92
Model name:          Intel(R) Celeron(R) CPU N3450 @ 1.10GHz
Stepping:            9
CPU MHz:             1521.740
CPU max MHz:         2200.0000
CPU min MHz:         800.0000
BogoMIPS:            2189.00
Virtualization:      VT-x
L1d cache:           24K
L1i cache:           32K
L2 cache:            1024K
NUMA node0 CPU(s):   0-3
Flags:               fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology tsc_reliable nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 sdbg cx16 xtpr pdcm sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave rdrand lahf_lm 3dnowprefetch cpuid_fault cat_l2 ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid ept_ad fsgsbase tsc_adjust smep erms mpx rdt_a rdseed smap clflushopt intel_pt sha_ni xsaveopt xsavec xgetbv1 xsaves dtherm ida arat pln pts arch_capabilities
```
I've got 3,7 GiB of RAM, and no swap.