perf(normalize): eliminate double normalization of params in callParts

callParts() was normalizing all parameters twice — once to calculate
paramLoc via SpanList.range(), then again to build the positional args.

The paramList computed on the first pass is already ASTv2.ExpressionNode[]
and can be passed directly to builder.positional(). Safe because:

- Symbol allocations (allocateFree/allocateNamed) are idempotent — they
  check indexOf/cache before allocating, so the second pass was pure waste.
- PositionalArguments stores exprs as readonly — no mutation concern.
- SpanList.range() only reads .loc from the nodes — no stored references.

The duplication dates back to the original 2020 commit (8e11b91) where
paramList was computed for SpanList.range() but then not reused for the
builder, with an identical .map(normalize) call created instead.

Impact (pnpm bench:precompile, prod dist, Apple M1 Max):
- normalize large (33374c): 18.92ms → 17.72ms (6%)
- precompile large: 43.01ms → 41.12ms (4%)

Author: johanrd

packages/@glimmer/syntax/lib/v2/normalize.ts

@@ -267,10 +267,7 @@ class ExpressionNormalizer {
     let namedLoc = this.block.loc(hash.loc);
     let argsLoc = SpanList.range([paramLoc, namedLoc]);
 
-    let positional = this.block.builder.positional(
-      params.map((p) => this.normalize(p, ASTv2.STRICT_RESOLUTION)),
-      paramLoc
-    );
+    let positional = this.block.builder.positional(paramList, paramLoc);
 
     let named = this.block.builder.named(
       hash.pairs.map((p) => this.namedArgument(p)),