fix(ivy): wrap non-statement assignment expressions in parentheses (angular#24862)

Previously, when translating an assignment expression (e.g. x = 3), the
translator would always print the statement as X = Y. However, if the
expression is included in a larger expression (X = (Y = Z)), the
translator would print "X = Y = Z" without regard for the outer
expression context.

Now, the translator understands when it's printing an expression
statement (X = Y;) vs an expression in a larger context (X = (Y = Z);)
and encapsulates the latter in parentheses.

PR Close angular#24862

Author: alxhub