Removes the tsickle dependency added when tsickle was added to the
transform compiler.
Added a test to ensure stray dependencies are not added and no
errors are introduced during module flattening.
Template expressions can now use a post-fix `!` operator
that asserts the target of the operator is not null. This is
similar to the TypeScript non-null assert operator. Expressions
generated in factories will be generated with the non-null assert
operator.
Closes: #10855
Reworked some of the code so asserts are no longer necessary.
Added additional and potentially redundant checks
Added checks where the null checker found real problems.
PR Close#16422