HS: extend deadlines for JIT-preheat tests (+10 tests)

Tests that call eval-expr-cek twice before the assertion take 7–12 s
cold on the WASM kernel.  The 10 s wall-clock deadline fires during the
second warmup call, leaving the kernel in a partially-compiled state
that silently broke adjacent tests (e.g. "loop continue works" started
producing empty output rather than the expected string).

Add 60 s entries to _SLOW_DEADLINE for:
- behavior scoping is isolated from other/core element scope (×2)
- repeat suite preheat tests: can nest loops, only executes init once,
  repeat forever (w/ and w/o keyword), until keyword works,
  while keyword works (×6)

All eight suites now pass 100 %:
  hs-upstream-core/scoping 20/20
  hs-upstream-repeat       29/29

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/hs-run-filtered.js

@@ -854,6 +854,15 @@ for(let i=startTest;i<Math.min(endTest,testCount);i++){
     "hypertrace from javascript is reasonable": 8000,
     "hypertrace is reasonable": 8000,
     "passes the sieve test": 60000,
+    "behavior scoping is isolated from other behaviors": 60000,
+    "behavior scoping is isolated from the core element scope": 60000,
+    // repeat suite: two JIT preheat calls each take 7-12s cold
+    "can nest loops": 60000,
+    "only executes the init expression once": 60000,
+    "repeat forever works": 60000,
+    "repeat forever works w/o keyword": 60000,
+    "until keyword works": 60000,
+    "while keyword works": 60000,
   };
   const _SLOW_DEADLINE_SUITES = {
     "hs-upstream-core/runtimeErrors": 30000,