RFR (S): 8238999: Remove MemRegion custom new/delete operator overloads

[Thomas Schatzl]

Hi all,

   can I have reviews for this small change to the MemRegion class to 
remove unnecessary new/delete overloads from MemRegion.

They return NULL if there is not enough memory. This is uncommon to do 
in Hotspot code.

All uses in the code either checks whether the allocation is non-NULL 
and then terminates the VM, or will just crash too.

It is easier to just replace the new[] calls with NEW_C_HEAP_ARRAY 
allocations and do the initialization manually.

cc'ing runtime because Coleen added the new operator for working around 
a Metaspace issue in JDK-8021954 years ago.

CR:
https://bugs.openjdk.java.net/browse/JDK-8238999
Webrev:
http://cr.openjdk.java.net/~tschatzl/8238999/webrev/
Testing:
hs-tier1-4

Thanks,
   Thomas