[wasm] Disable WasmCodeManagerTest when run under lsan

Disabling while investigating referenced bug.

Bug: chromium:787976
Change-Id: I0388d8902f40e3b2f3759542befd3c6c20b6da38
Reviewed-on: https://chromium-review.googlesource.com/786325
Commit-Queue: Mircea Trofin <mtrofin@chromium.org>
Commit-Queue: Brad Nelson <bradnelson@chromium.org>
Reviewed-by: Brad Nelson <bradnelson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#49593}

test/unittests/wasm/wasm-heap-unittest.cc

@@ -151,6 +151,8 @@ TEST_F(DisjointAllocationPoolTest, MergingSkipLargerSrcWithGap) {
   CheckLooksLike(a, {{10, 15}, {20, 35}, {36, 40}});
 }
 
+// TODO(chromium:787976): remove conditional compilation when bug is fixed
+#if !LEAK_SANITIZER
 class WasmCodeManagerTest : public TestWithIsolate {
  public:
   using NativeModulePtr = std::unique_ptr<NativeModule>;
@@ -385,6 +387,7 @@ TEST_F(WasmCodeManagerTest, LookupWorksAfterRewrite) {
     CHECK_EQ(code1_1, manager.LookupCode(code1_1->instructions().start()));
   }
 }
+#endif
 
 }  // namespace wasm_heap_unittest
 }  // namespace wasm