Remove "EOF-newline" lexer hack

In preparation for an upcoming change
Makes for nicer error messages, complaining about EOF instead of newlines
The hack had to be kept for the lexer raw mode to avoid a bug;
see the relevant code comment for more info.

test/asm/pc-operand.asm

@@ -3,11 +3,13 @@ SECTION "fixed", ROM0[0]
 	rst @    ; rst 0
 	ld de, @ ; ld de, 1
 	bit @, h ; bit 4, h
-	db @, @  ; db 6, 7
+	jr @     ; jr 6
 
 SECTION "floating", ROM0
 
 	rst @    ; rst 8
 	ld l, @  ; ld l, 9
-	dw @, @  ; dw 11, 13
-	dl @, @  ; dl 15, 19
+	db @, @  ; db 11, 12
+	dw @, @  ; dw 13, 15
+	dl @, @  ; dl 17, 21
+	jr @     ; jr 25