clean up /tmp/test-run- files

Summary: While investigating t5037772 I noticed we don't clean these files up. Seems prudent to.

Reviewed By: @JoelMarcey

Differential Revision: D1535223
VASM register-coalescing via hinting

Summary: Add hints to interval uses associated with copies, to try to
pick the same register.

Reviewed By: @swtaarrs

Differential Revision: D1486006
Assign vasm registers to all SSATmps

Summary: Flip x64 code generation over to virtual registers. If all uses and
defs of an SSATmp only access a whole cell, assign a "wide" location.
If a tmp is defined by DefConst, assign a cpool-backed virtual register.
If the type does not have a known DataType, assign a type register.
This intentionally ignores src/dest constraints, which will be phased
out.

Reviewed By: @swtaarrs

Differential Revision: D1530245
typechecker: recognize binary int literals

Summary: The binary int syntax (##0b101## for ##5##) is a handy syntax
 for certain use cases (such as declaring constants for bitwise
 masks), which wasn't being lexed as an int literal as an oversight.
 As with ##0x##, we don't recognize the alternate form ##0B##.

Reviewed By: @jwatzman

Differential Revision: D1533071
Remove xls support in x64 backend

Summary: D1530245 Removed the calls to it, this removes the now-dead code.

Reviewed By: @markw65

Differential Revision: D1530650