Request for reviews (M): 6947341: JVM Crash running Oracle ATG CRMDemo

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/6947341/webrev

Fixed 6947341: JVM Crash running Oracle ATG CRMDemo

Missing protected page below heap with compressed oops
which use narrow_oop_base and implicit null check.
It is caused by ReservedSpace code misses checks that OS
reserved heap at requested address.

Before 6951686 fix Linux will reserve heap memory at address
which is not requested for compressed oops VM (usually above
32Gb virtual address: 0x00002aaaae200000). But VM thinks
it did reserve at requested address and it does not need
protected page below heap, so the code in protect_noaccess_prefix()
is not executed.

Solution:
Add missing checks. I also added few asserts and prints
to make sure memory reservation done correctly for
compressed oops.

Verified with CRMDemo.