fixes regression #20746; remove string copies for ORC booted compiler (#20776)

* fixes #20746; remove string copies for ORC booted compiler

* add a test case

* use `cursor` thanks to @beef331

* for old compilers

* change file extension

* change test cases

tests/vm/t20746.nim

@@ -0,0 +1,13 @@
+discard """
+  timeout: 10
+  joinable: false
+  output: "fine"
+"""
+
+func addString(): string =
+  let x = newString(1000000)
+  for i in 0..<1000000:
+    discard x[i]
+
+const translationTable = addString()
+echo "fine"