RFR (S): 8004747: Remove last_entry from VM_STRUCT macros

[Mikael Vidstedt]

Please review the following change:

Webrev: http://cr.openjdk.java.net/~mikael/8004747/webrev.00/

Background:

This patch does 3 things (depending on how you count it):

1. Move the call to generating the last entry for the VM structures 
database

The vmStructs functionality is a macro based way of creating a database 
of information about VM internal structures, types and constants.

The database for structures is defined in runtime/vmStructs.cpp in an 
array called localHotSpotVMStructs. The content of the array is 
generated with calls to a few different macros (VM_STRUCTS, 
VM_STRUCTS_PARALLELGC, VM_STRUCTS_CMS, VM_STRUCTS_G1, VM_STRUCTS_CPU and 
VM_STRUCTS_OS_CPU respectively). Common for all these macros is the fact 
that the last argument passed in is another macro 
(GENERATE_VM_STRUCT_LAST_ENTRY) which is a generator for the end 
marker/last entry in the database; a special entry which can be easily 
located by an external consumer of the information.

Even though the end marker generator macro 
(GENERATE_VM_STRUCT_LAST_ENTRY) is passed to all the VM_STRUCT* macros, 
the actual end marker must be generated once and only once. The way this 
is currently handled is that only the last VM_STRUCT macro, which 
happens to be VM_STRUCTS_OS_CPU, actually makes use of its last argument 
and adds it to the end of the array.

Not only is this fairly complex to understand, it's also more fragile 
than it needs to be.

This change removes the last argument for all the VM_STRUCT macros and 
instead explicitly inserts the end marker at the end of the 
localHotSpotVMStructs array.

The same VM_STRUCTS macros are being used in VMStructs::init to do type 
checking. Instead of passing the end marker generator into the macros 
the last parameter is instead CHECK_SENTINEL, which is defined to expand 
to nothing, which means it can be safely removed.

2. Move the end marker generating for the VM types, VM int constants and 
VM long constants databases

Repeat the exact above story, but replace anything called Structs/STRUCT 
with Types/TYPES, IntConstants/INT_CONSTANTS and 
LongConstants/LONG_CONSTANTS respectively.

3. Minor prettification

In addition to the above the change also removes some superfluous 
backslashes from a few of the VM_STRUCT* macro calls.

Thanks,
Mikael