[tilegx] TileGX register bit map needs 64bit width.
[tilegx] JSReturnSequence length should be 8 instructions for tilegx.
[tilegx] Register::bit should be 64bit.

  And revert previous kJSReturnSequenceInstructions fix.

  kJSReturnSequenceInstructions should be 7, because the first pop
  operation is with offset 0, so no need of an extra sp adjust insn.
[tilegx] TileGX argv is in r4, no on stack because we have 10 arg regs.

  Also improved some register nameing.
[tilegx] For 64bit target, the Smi shift amount should be 32, not 1.
[tilegx] Use "lnk" to calculate pc.

  Remove mips "bal" based pc calculation instruction sequences, should
use TileGX "lnk" instruction.
[tilegx] Enable hooks in frames-tilegx.cc.
[tilegx] Unify register naming.