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/macro-eof.asm

@@ -0,0 +1,6 @@
+; Macro invocations not followed by a newline may scan an EOF;
+; If this is the case, it shouldn't cause the parse to end before the macro is expanded
+mac: macro
+	PRINTLN "Hi beautiful"
+endm
+	mac