fix(tests): deflake LocalInterpreter timeout tests (#10630)

Two tests used execution_timeout=0.1, which only has to cover one
request/response round trip to the worker. On loaded CI runners that
round trip occasionally exceeds 100ms, so the timeout fires on code
that should return immediately (execute("if")) or before the host
tool request arrives.

Use a 1s timeout, exclude worker startup from the elapsed measurement,
and block the host tool on an event instead of a short sleep so the
test still fails if execute() waits for a blocked tool.

Amp-Thread-ID: https://ampcode.com/threads/T-01a13070-310d-739a-abc1-9b4c33bffaa6

Co-authored-by: Amp <amp@ampcode.com>
Co-authored-by: Isaac Miller <isaac@cmpnd.ai>

Author: 3 people

tests/primitives/test_local_interpreter.py

@@ -161,7 +161,7 @@ def test_guest_cannot_corrupt_interpreter_owned_globals_across_executions():
 
 
 def test_errors_are_recoverable_but_timeout_is_terminal():
-    interpreter = dspy.LocalInterpreter(execution_timeout=0.1)
+    interpreter = dspy.LocalInterpreter(execution_timeout=1)
     with pytest.raises(SyntaxError):
         interpreter.execute("if")
     with pytest.raises(CodeExecutionError, match="ZeroDivisionError"):
@@ -223,20 +223,23 @@ def echo(value):
 
 def test_execution_timeout_does_not_wait_for_blocked_host_tool():
     tool_started = threading.Event()
+    release_tool = threading.Event()
 
     def blocked():
         tool_started.set()
-        time.sleep(1)
+        release_tool.wait(timeout=10)
         return 42
 
-    interpreter = dspy.LocalInterpreter(tools={"blocked": blocked}, execution_timeout=0.1)
+    interpreter = dspy.LocalInterpreter(tools={"blocked": blocked}, execution_timeout=1)
+    interpreter.start()
     started = time.monotonic()
     with pytest.raises(CodeInterpreterError, match="exceeded execution timeout"):
         interpreter.execute("blocked()")
     elapsed = time.monotonic() - started
+    release_tool.set()
 
-    assert tool_started.wait(timeout=1)
-    assert elapsed < 0.5
+    assert tool_started.wait(timeout=5)
+    assert elapsed < 5
     with pytest.raises(CodeInterpreterError, match="shut down"):
         interpreter.execute("1")