Warn about DWARF inhibiting binaryen opts only when binaryen optimizes (#25889)

If we don't optimize, the warning can be confusing.

Author: kripken

test/test_other.py

@@ -13412,8 +13412,9 @@ def test_wasm_worker_preprocessor_flags(self):
   @parameterized({
     # we will warn here since -O2 runs the optimizer and -g enables DWARF
     'O2_g': (True, ['-O2', '-g']),
-    # asyncify will force wasm-opt to run as well, so we warn here too
-    'asyncify_g': (True, ['-sASYNCIFY', '-g']),
+    # asyncify will force wasm-opt to run as well, but without optimizations, so
+    # we do not warn about the lack of optimization
+    'asyncify_g': (False, ['-sASYNCIFY', '-g']),
     # with --profiling-funcs however we do not use DWARF (we just emit the
     # names section) and will not warn.
     'O2_pfuncs': (False, ['-O2', '--profiling-funcs']),

test/third_party/posixtestsuite

@@ -2350,7 +2350,7 @@ def phase_binaryen(target, options, wasm_target):
       intermediate_debug_info -= 1
     # currently binaryen's DWARF support will limit some optimizations; warn on
     # that. see https://github.com/emscripten-core/emscripten/issues/15269
-    if settings.GENERATE_DWARF:
+    if settings.GENERATE_DWARF and should_run_binaryen_optimizer():
       diagnostics.warning('limited-postlink-optimizations', 'running limited binaryen optimizations because DWARF info requested (or indirectly required)')
     with ToolchainProfiler.profile_block('wasm_opt'):
       building.run_wasm_opt(wasm_target,