Refactoring in preparation for lazy skolemisation

* Make HsMatchContext and HsStmtContext be parameterised over the
  function name itself, rather than over the pass.
  See [mc_fun field of FunRhs] in Language.Haskell.Syntax.Expr
    - Replace types
        HsMatchContext GhcPs --> HsMatchContextPs
        HsMatchContext GhcRn --> HsMatchContextRn
        HsMatchContext GhcTc --> HsMatchContextRn  (sic! not Tc)
        HsStmtContext  GhcRn --> HsStmtContextRn
    - Kill off convertHsMatchCtxt

* Split GHC.Tc.Type.BasicTypes.TcSigInfo so that TcCompleteSig (describing
  a complete user-supplied signature) is its own data type.
    - Split TcIdSigInfo(CompleteSig, PartialSig) into
        TcCompleteSig(CSig)
        TcPartialSig(PSig)
    - Use TcCompleteSig in tcPolyCheck, CheckGen
    - Rename types and data constructors:
        TcIdSigInfo         --> TcIdSig
        TcPatSynInfo(TPSI)  --> TcPatSynSig(PatSig)
    - Shuffle around helper functions:
        tcSigInfoName           (moved to GHC.Tc.Types.BasicTypes)
        completeSigPolyId_maybe (moved to GHC.Tc.Types.BasicTypes)
        tcIdSigName             (inlined and removed)
        tcIdSigLoc              (introduced)
    - Rearrange the pattern match in chooseInferredQuantifiers

* Rename functions and types:
    tcMatchesCase         --> tcCaseMatches
    tcMatchesFun          --> tcFunBindMatches
    tcMatchLambda         --> tcLambdaMatches
    tcPats                --> tcMatchPats
    matchActualFunTysRho  --> matchActualFunTys
    matchActualFunTySigma --> matchActualFunTy

* Add HasDebugCallStack constraints to:
    mkBigCoreVarTupTy, mkBigCoreTupTy, boxTy,
    mkPiTy, mkPiTys, splitAppTys, splitTyConAppNoView_maybe

* Use `penv` from the outer context in the inner loop of
  GHC.Tc.Gen.Pat.tcMultiple

* Move tcMkVisFunTy, tcMkInvisFunTy, tcMkScaledFunTys down the file,
  factor out and export tcMkScaledFunTy.

* Move isPatSigCtxt down the file.

* Formatting and comments

Co-authored-by: Vladislav Zavialov <vlad.z.4096@gmail.com>