Remove two redundant shapes from the JavaScript output

[marevol]

Problem

MungedCodeGenerator emits more bytes than it needs to in two places. Both are already recorded in JsGoldenFileTest's jQuery gap table as Release 2 work — this is that work.

1. A ; immediately before a }

function f(){var a=1;return a;}  ->  function f(){var b=1;return b;}   // before
                                 ->  function f(){var b=1;return b}    // after
if(a)b();else c();               ->  if(a){b();}else{c();}             // before
                                 ->  if(a){b()}else{c()}               // after

} ends the statement on its own. Upstream YUI removes it too ("Remove ';' when followed by a '}'", CHANGELOG 1.1), and every golden file in src/test/resources carries zero ;}.

2. Parentheses around a conditional on an assignment's right-hand side

x=y?z:w;  ->  x=(y?z:w);   // before
          ->  x=y?z:w;     // after

An assignment's right-hand side is an AssignmentExpression, which a conditional already is. Upstream emits this without parentheses.

Fix

Every site that emits a block now goes through one visitStatementList, which skips the separator after the last statement. The synthetic braces that if/else and the loop bodies wrap a single statement in never needed a ; at all — it was appended immediately before the } in the same expression.

Switch cases are the one place the position matters: only the last case's last statement is followed by the switch's }. Every other one keeps its ;, otherwise case 1:b()case 2: is a syntax error. Pinned in RedundantOutputTest.

needsParentheses returned true for every ConditionalExpression under any InfixExpression; it now excludes an Assignment's right operand only. Everything else keeps its parentheses, because every other operator binds tighter than ?: — x=a+(b?c:d) without them re-parses as (a+b)?c:d.

Line breaks are unaffected. A statement that gave up its ; is still a statement boundary, but nothing in the output says so, so markSafeBreak is no longer offered at that position — the } that follows immediately offers one anyway. Every recorded break offset stays verifiable as following a ; or a }, which is what ModernJsTest.assertEveryLineBreakIsAtAStatementBoundary checks.

Measurements

jquery-1.6.4.js: 104,815 → 103,468 bytes (−1.3%).

contributor to the golden gap	before	after
missing ; before }	+1,259	0
extra parentheses	+128	+84
longer munged names	+1,280	+1,325
extra spaces	+81	+81
fewer braces	−62	−62
total gap	2,823	1,476

;} now matches the golden exactly (0). What is left is almost entirely short-name allocation, which stays Release 2 work.

Corpus: 576 real-world scripts (jQuery, Bootstrap, Vue/webpack and Next.js bundles, FullCalendar, DOMPurify, marked, and the Fess/CodeLibs front ends) — 11,436,756 → 11,357,307 bytes, −0.69%. No file grew.

Safety: every one of those 576 outputs was run through node --check. The 39 that do not parse fail identically before this change — none is new, and they are a separate pre-existing issue. No new parse failure and no new second-pass instability across the same corpus.

Test changes

• Expectations that pinned the old spelling are updated in place. The replacement was driven from the measured (expected, actual) pairs reported by the failing run rather than by hand, so only exact prior expectations were rewritten.
• RedundantOutputTest (new, 11 cases) pins both new shapes together with the cases that must keep their separator or their parentheses.
• Size pins in JsGoldenFileTest and IdempotencyTest, and the gap table, are updated with re-measured numbers.
• issue71.js.min is regenerated. That golden was written for this fork rather than taken from upstream — upstream 2.4.8 drops the "use strict" the fixture exists to test.

Full suite: 775 tests, 0 failures, 3 skipped.