ci: fix lint-testsuite job

The list_broken make target will transitively depend on the
calibrate.out target, which used STAGE1_GHC instead of TEST_HC. It
really should be TEST_HC since that's what get passed in the gitlab CI
config.

testsuite/timeout/Makefile

@@ -51,11 +51,7 @@ boot all :: calibrate.out $(TIMEOUT_PROGRAM)
 
 calibrate.out:
 	$(RM) -f TimeMe.o TimeMe.hi TimeMe TimeMe.exe
-	$(PYTHON) calibrate '$(STAGE1_GHC)' > $@
-# We use stage 1 to do the calibration, as stage 2 may not exist.
-# This isn't necessarily the compiler we'll be running the testsuite
-# with, but it's really the performance of the machine that we're
-# interested in
+	$(PYTHON) calibrate '$(TEST_HC)' > $@
 
 endif
 endif
@@ -66,4 +62,3 @@ clean distclean maintainer-clean:
 	$(RM) -rf install-inplace
 	$(RM) -f calibrate.out
 	$(RM) -f Setup Setup.exe Setup.hi Setup.o
-