Support stage 1 Template Haskell (non-quasi) quotes, fixes #10382.
Summary: This commit adds stage 1 support for Template Haskell quoting, e.g. [| ... expr ... |], which is useful for authors of quasiquoter libraries that do not actually need splices. The TemplateHaskell extension now does not unconditionally fail; it only fails if the renamer encounters a splice that it can't run. In order to make sure the referenced data structures are consistent, template-haskell is now a boot library. There are some minor BC changes to template-haskell to make it boot on GHC 7.8. Note for reviewer: big diff changes are simply code being moved out of an ifdef; there was no other substantive change to that code. Signed-off-by: Edward Z. Yang <email@example.com> Test Plan: validate Reviewers: simonpj, austin, goldfire Subscribers: bgamari, thomie Differential Revision: https://phabricator.haskell.org/D876 GHC Trac Issues: #10382