[wasm][cleanup] Remove minor debug-only flag

The same functionality can be achieved by just setting a breakpoint in
that function.

R=ahaas@chromium.org

Bug: v8:9810
Change-Id: Ieb5e99b5c2f0b492e32e75cae0c0b9292accd932
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1888072Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64646}

src/flags/flag-definitions.h

@@ -685,8 +685,6 @@ DEFINE_BOOL(liftoff, false,
             "enable Liftoff, the baseline compiler for WebAssembly")
 DEFINE_BOOL(trace_liftoff, false,
             "trace Liftoff, the baseline compiler for WebAssembly")
-DEFINE_DEBUG_BOOL(wasm_break_on_decoder_error, false,
-                  "debug break when wasm decoder encounters an error")
 DEFINE_BOOL(trace_wasm_memory, false,
             "print all memory updates performed in wasm code")
 // Fuzzers use {wasm_tier_mask_for_testing} together with {liftoff} and

src/wasm/decoder.h

@@ -285,11 +285,6 @@ class Decoder {
   void verrorf(uint32_t offset, const char* format, va_list args) {
     // Only report the first error.
     if (!ok()) return;
-#if DEBUG
-    if (FLAG_wasm_break_on_decoder_error) {
-      base::OS::DebugBreak();
-    }
-#endif
     constexpr int kMaxErrorMsg = 256;
     EmbeddedVector<char, kMaxErrorMsg> buffer;
     int len = VSNPrintF(buffer, format, args);