Possibly hard REAPER crash when obtaining number of FX

[helgoboss]

Observed this in the wild (reported by sonicsoul):

Thread 0 Crashed:: reaper Dispatch queue: com.apple.main-thread
0   REAPER                        	       0x1032e50c1 TrackFX_GetCount(MediaTrack*) + 17
1   helgobox-x64.vst.dylib        	       0x11d2892a9 0x11c887000 + 10494633
2   helgobox-x64.vst.dylib        	       0x11d27d27e 0x11c887000 + 10445438
3   helgobox-x64.vst.dylib        	       0x11d2772f1 0x11c887000 + 10420977
4   helgobox-x64.vst.dylib        	       0x11ce69b28 0x11c887000 + 6171432
5   helgobox-x64.vst.dylib        	       0x11d4ffd0f 0x11c887000 + 13077775
6   helgobox-x64.vst.dylib        	       0x11cec0126 0x11c887000 + 6525222
7   helgobox-x64.vst.dylib        	       0x11ceb1b33 0x11c887000 + 6466355
8   helgobox-x64.vst.dylib        	       0x11cea2d42 0x11c887000 + 6405442
9   helgobox-x64.vst.dylib        	       0x11d0d20e3 0x11c887000 + 8696035
10  helgobox-x64.vst.dylib        	       0x11dfa1ae7 0x11c887000 + 24226535
11  REAPER                        	       0x1033ae594 CSurf_Run() + 1316
12  REAPER                        	       0x102ff6b4f runMiscTimers1() + 7087
13  REAPER                        	       0x10307e607 Main_OnTimer(HWND__*, unsigned long) + 1751
14  REAPER                        	       0x10307e607 Main_OnTimer(HWND__*, unsigned long) + 1751
15  REAPER                        	       0x10307e607 Main_OnTimer(HWND__*, unsigned long) + 1751
16  REAPER                        	       0x10307e607 Main_OnTimer(HWND__*, unsigned long) + 1751