getting rid of pointer[idx] in ast, instead always use @(ptr+idx)

compiler/test/vm/TestCompilerVirtual.kt

@@ -288,9 +288,6 @@ mylabel:
 
     test("nesting with overlapping names is ok (doesn't work for 64tass)") {
         val src="""
-%import textio
-%zeropage basicsafe
-
 main {
     sub start() {
         main()