[Gardening][AST] Eliminate 'numParameterLists'. (#22824)

Leftover from bfc4121

Author: rintaro

include/swift/AST/Decl.h

@@ -5717,12 +5717,12 @@ class AccessorDecl final : public FuncDecl {
                AccessorKind accessorKind, AbstractStorageDecl *storage,
                SourceLoc staticLoc, StaticSpellingKind staticSpelling,
                bool throws, SourceLoc throwsLoc,
-               unsigned numParameterLists, GenericParamList *genericParams,
+               bool hasImplicitSelfDecl, GenericParamList *genericParams,
                DeclContext *parent)
     : FuncDecl(DeclKind::Accessor,
                staticLoc, staticSpelling, /*func loc*/ declLoc,
                /*name*/ Identifier(), /*name loc*/ declLoc,
-               throws, throwsLoc, numParameterLists, genericParams, parent),
+               throws, throwsLoc, hasImplicitSelfDecl, genericParams, parent),
       AccessorKeywordLoc(accessorKeywordLoc),
       Storage(storage) {
     Bits.AccessorDecl.AccessorKind = unsigned(accessorKind);