Optimizing: Lazy creation of Handle<>s in RTP.

This reduces the number of StackHandleScope<>s that we
allocate, especially when we're inlining many methods.
Previously, each RTP would create 4 handles in the ctor
which is actually the same as kNumReferencesPerScope.

Change-Id: Ib6767993b1e89913a91275f0ef66dac786bccb6c
2 files changed