RFR(XS): 8038422: CDS test failed: assert((size % os::vm_allocation_granularity()) == 0) failed when limiting SharedMiscDataSize

[Yumin Qi]

Please review

   webrev: http://cr.openjdk.java.net/~minqi/8038422/
   bug: https://bugs.openjdk.java.net/browse/JDK-8038422

   Summary: In debug version, the assert is against 
os::vm_allocation_granularity(), but in initialization, we use 
os::vm_page_size() to align the allocation size. In windows, 
_vm_page_size and _vm_allocation_granularity may not be same.

    _vm_page_size = si.dwPageSize;
   _vm_allocation_granularity = si.dwAllocationGranularity;

This lead to the assertion failed. We should align allocation size with 
_vm_allocation_granularity.

   test: manual testing on Windows.(which is the error on)
   JPRT
   jtreg

   Thanks
   Yumin