message: refactor(ngcc): tighten method parameter type to avoid redundant check
  `Esm5ReflectionHost#getInnerFunctionDeclarationFromClassDeclaration()`
  was already called with `ts.Declaration`, not `ts.Node`, so we can
  tighten its parameter type and get rid of a redundant check.
  `getIifeBody()` (called inside
  `getInnerFunctionDeclarationFromClassDeclaration()`) will check whether
  the given `ts.Declaration` is a `ts.VariableDeclaration`.
  PR Close
diff: @@ -291,16 +291,14 @@ export class Esm5ReflectionHost extends Esm2015ReflectionHost {
  *
  * Given the outer variable declaration, we want to get to the inner function declaration.
  *
  - * @param node a node that could be the variable expression outside an ES5 class IIFE.
  + * @param decl a declaration node that could be the variable expression outside an ES5 class IIFE.
  * @param checker the TS program TypeChecker
  * @returns the inner function declaration or `undefined` if it is not a "class".
  */
  - protected getInnerFunctionDeclarationFromClassDeclaration(node: ts.Node): ts.FunctionDeclaration
  + protected getInnerFunctionDeclarationFromClassDeclaration(decl: ts.Declaration): ts.FunctionDeclaration
  |undefined {
  - if (!ts.isVariableDeclaration(node)) return undefined;
  -
  // Extract the IIFE body (if any).
  - const iifeBody = getIifeBody(node);
  + const iifeBody = getIifeBody(decl);
  if (!iifeBody) return undefined;
  // Extract the function declaration from inside the IIFE.
  