ZGC runs out of memory with appcds GCDuringDump.java on linux/aarch64

This test should not run out of memory. The tests specifies a 32MB heap. When running on Linux/x64, the heap usage is never over 50% after GC finishes.

However, in one recent mach5 run on linux/aarch64, we get lots of OOM and eventually CDS dumping failed due to JDK-8254309:

$ grep ZHeap hs_err_pid22387.log
 ZHeap used 32M, capacity 32M, max capacity 32M
 ZHeap used 32M, capacity 32M, max capacity 32M
 ZHeap used 32M, capacity 32M, max capacity 32M
 ....