[build] Fix gcc build fails with msan enabled

Closes https://github.com/dart-lang/sdk/pull/62635

GitOrigin-RevId: 5a1772f71c3ebdf96d8df6217146bcfaae6fe7ae
Change-Id: I5bc00d5fd02a8dae55c983bb53565874a4ea528e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/479680
Commit-Queue: Slava Egorov <vegorov@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>

sdk/BUILD.gn

@@ -395,9 +395,13 @@ if (!using_sanitizer && current_os == "linux" &&
   if (current_cpu == "x64" || current_cpu == "arm64") {
     sanitizers += [
       "asan",
-      "msan",
       "tsan",
     ]
+    if (is_clang) {
+      sanitizers += [
+        "msan",
+      ]
+    }
   } else if (current_cpu == "riscv64") {
     # Fuchsia Clang is missing the riscv64 MSAN runtime.
     sanitizers += [