[dmd-internals] runnable/interpret.d + -O == failure

[Brad Roberts]

I switched the linux auto-tester over to run the full test suite rather than
just the quick version (just the no-args version of every test).  I figured it's
automated and the box is idle 99% of the time anyway.. so it's worth spending
the extra cycles to get more test coverage instead of cycling faster.

Good thing I did. :)

It's failing (reliably) on runnable/interpret.d when building with -O.  It ran
successfully with a bunch of other combinations.

first failed:
../src/dmd -Irunnable  -O -odtest_results/runnable
-oftest_results/runnable/interpret runnable/interpret.d

passed:
<none>
-inline
-release
-inline -release
-gc
-inline -gc
-release -gc
-inline -release -gc

I'll go spend a little time narrowing down exactly which test fails and do a bit
of regression hunting through the dmd changes since the last full release.  But,
something's currently not perfect.

Later,
Brad