Request for reviews (S): 6706829: Compressed Oops: add debug info for narrow oops

[Vladimir Kozlov]

http://webrev.invokedynamic.info/kvn/6706829/index.html

Fixed 6706829: Compressed Oops: add debug info for narrow oops

Problem:
Currently C2 generates decoding of narrow oops to provide inputs for debug info
which does not support narrow oops.

Solution:
Add support for narrow oops in debug info to avoid decoding.
Use 32 bits for the debug info Location value and use 4 bits for type.

Generate narrow oops in debug info only for uncommon traps for now.
For regular calls and safepoints additional checks should be added
to make sure that DecodeN is not used after the call (safepoint)
for which it was replaced with its input in debug info.
Such change is more complex and will be done later.

Reviewed by:
Fix verified (y/n): y, generated code

Other testing:
JPRT