The patch fixes various code generation issues found during testing of Cross-test and PNaCL smoke-test framework.

     1)	To keep track of branches to same label, relative position of the branch from previous branch is used.
     2)	Fixed encoding of conditional mov instructions
     3)	Added MovFP64ToI64 instruction for f64 to i64 move
     4)	Handled vector-types in Phi nodes
     5)	Fixed alignment of spilled vector arguments on stack
     6)	Save-restore FP registers
     7)	Fixed code generation for Zext and Sext operations
     8)	Fixed InsertElement for vi16x8 type

R=stichnot@chromium.org

Patch from Jaydeep Patil <jaydeep.patil@imgtec.com>.

Review-Url: https://codereview.chromium.org/2619943003 .