Test of asm references.

-- example/label_example.s --
TEXT ·JumpDemo(SB), $0-0
label1: //@loc(defLabel, "label1")
    JMP label1 //@loc(refLabel, "label1")

-- example/in_package_ref.s --
TEXT ·Foo(SB), $0-8 //@loc(defFooAsm, "·Foo")
    RET

TEXT ·Bar(SB), $0-8
    CALL ·Foo(SB) //@loc(callFooAsm, "·Foo")
    RET

-- example/example_data.s --
DATA ·myGlobal+0(SB)/8, $42
GLOBL ·myGlobal(SB), NOPTR, 8

TEXT ·UseGlobal(SB), $0-0
    MOVQ ·myGlobal(SB), AX //@loc(refMyGlobal, "·myGlobal")
    RET
