mk: Add check-secondary target for tests with no x-platform risk.

We'll use this to run a subset of the test suite onto a dedicated
bot.

This puts the grammar tests and the pretty-printer tests under
check-secondary. It leanves the pretty tests under plain `check`
for now, until the new bot is added to take over.

Because check-secondary is not run as part of `make check` there
will be a set of tests that most users never run and are only
checked by bors. I think this will be ok because grammar tests
should rarely regress, and the people regressing such tests
should have the fortitude to deal with it.

Author: brson

mk/tests.mk

@@ -192,8 +192,14 @@ check-docs: cleantestlibs cleantmptestlogs check-stage2-docs
 # NOTE: Remove after reprogramming windows bots
 check-fast: check-lite
 
+check-all: check check-secondary
+
+check-secondary: check-syntax check-pretty
+
 check-syntax: check-lexer
 
+check-pretty: check-stage2-T-$(CFG_BUILD)-H-$(CFG_BUILD)-pretty-exec
+
 .PHONY: cleantmptestlogs cleantestlibs
 
 cleantmptestlogs: