PreserveImportsExportsJS fuzzer: Handle JS differences in stack traces (#8610)

Generalize our stack-trace ignoring code, as it turns out the JS
parts of traces can differ based on optimizations.

Author: kripken

scripts/fuzz_opt.py

@@ -2223,13 +2223,14 @@ def do_run(self, vm, js, wasm):
                 # must also remove the specific trap, as Binaryen can change
                 # that.
                 line = 'TRAP'
-            elif 'wasm://' in line or '(<anonymous>)' in line:
+            elif line.startswith('    at '):
                 # This is part of a stack trace like
                 #
                 #     at wasm://wasm/12345678:wasm-function[42]:0x123
                 #     at (<anonymous>)
+                #     at file.js
                 #
-                # Ignore it, as traces differ based on optimizations.
+                # Ignore it, as details of traces differ based on optimizations.
                 continue
             cleaned.append(line)
         return '\n'.join(cleaned)