RFR(S) 8134898: Small fixes found during JVMCI work

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/8134898/webrev/
https://bugs.openjdk.java.net/browse/JDK-8134898

During review of JVMCI changes we were asked to push not related small 
changes separately.

Removed jre/ from jdk paths in makefiles since jdk9 does not have it 
anymore.
Solaris vm.make and buildtree.make missed changes other unix platforms have.
Fix type in doc.
Added -DCHECK_UNHANDLED_OOPS to debug build. I very strongly want to do 
that.
It is the only incompatibility in memory layout between fastdebug and 
debug VM. We maintained such compatibility for long time and it was 
broken with 7195622 changes.
For AOT project it is very important to keep compatibility because we 
use fastdebug VM for JAOTC tool to compile aot code and we want to be 
able use debug VM to debug execution of aot code.
Note, using debug VM with JAOTC will take 5-10 times longer to compile.

Thanks,
Vladimir