a metaspace/gc/firstGC_99m test sets -XX:metaspaceSize=99m and expects that first GC will happen when committed amount of metaspace will be around 99m.

But on Win32 it might happen a bit earlier:

%## GC happened at the wrong moment, the amount of committed space significantly differs from the expected amount
%## Real : 103415808
%## Exepcted: 103809024

The test is based on: JDK 8 GC tuning document
 
 * Quating: Java SE 8 HotSpot[tm] Virtual Machine Garbage Collection Tuning
 * <pre>
 * Class metadata is deallocated when the corresponding Java class is unloaded.
 * Java classes are unloaded as a results of garbage collection and garbage
 * collections may be induced in order to unload classes and deallocate class
 * metadata. When the space used for class metadata reaches a certain level
 * (call it a high-water mark), a garbage collection is induced.
 *
 * The flag MetaspaceSize can be set higher to avoid early garbage collections
 * induced for class metadata. The amount of class metadata allocated for
 * an application is application dependent and general guidelines do not
 * exist for the selection of MetaspaceSize. The default size of MetaspaceSize
 * is platform dependent and ranges from 12 MB to about 20 MB.