`load' doesn't cause the compiler to be loaded in some cases

`load' doesn't cause the compiler to be loaded in some cases

* module/system/base/compile.scm (compiled-file-name): Add a comment.
* module/ice-9/boot-9.scm (load): Avoid loading up (system base compile)
  just to compute an autocompiled file name. Fixes the issue whereby
  guile-tools snarf-check-and-output-texi was inadvertantly loading up
  srfi-1, and thereby a stale library, just to see if guile-tools itself
  had a compiled version.

  Not sure what the right unit test is here, other than vigilance.