[wasm] Fix -Wsign-compare warnings.

test/cctest/wasm/test-run-wasm-interpreter.cc

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include <memory>
 
@@ skipping 184 matching lines @@
   FOR_UINT32_INPUTS(a) {
     for (uint32_t b = 11; b < 3000000000u; b += 1000000000u) {
       thread->Reset();
       WasmVal args[] = {WasmVal(*a), WasmVal(b)};
       thread->PushFrame(r.function(), args);
 
       for (int i = 0; i < kNumBreakpoints; i++) {
         thread->Run();  // run to next breakpoint
         // Check the thread stopped at the right pc.
         CHECK_EQ(WasmInterpreter::PAUSED, thread->state());
-        CHECK_EQ(kLocalsDeclSize + offsets[i], thread->GetBreakpointPc());
+        CHECK_EQ(static_cast<size_t>(kLocalsDeclSize + offsets[i]),
+                 thread->GetBreakpointPc());
       }
 
       thread->Run();  // run to completion
 
       // Check the thread finished with the right value.
       CHECK_EQ(WasmInterpreter::FINISHED, thread->state());
       uint32_t expected = (*a) + (b);
       CHECK_EQ(expected, thread->GetReturnValue().to<uint32_t>());
     }
   }
@@ skipping 57 matching lines @@
         interpreter->SetBreakpoint(r.function(), kLocalsDeclSize + offsets[0],
                                    do_break);
         thread->Reset();
         WasmVal args[] = {WasmVal(*a), WasmVal(b)};
         thread->PushFrame(r.function(), args);
 
         if (do_break) {
           thread->Run();  // run to next breakpoint
           // Check the thread stopped at the right pc.
           CHECK_EQ(WasmInterpreter::PAUSED, thread->state());
-          CHECK_EQ(kLocalsDeclSize + offsets[0], thread->GetBreakpointPc());
+          CHECK_EQ(static_cast<size_t>(kLocalsDeclSize + offsets[0]),
+                   thread->GetBreakpointPc());
         }
 
         thread->Run();  // run to completion
 
         // Check the thread finished with the right value.
         CHECK_EQ(WasmInterpreter::FINISHED, thread->state());
         uint32_t expected = (*a) & (b);
         CHECK_EQ(expected, thread->GetReturnValue().to<uint32_t>());
       }
     }
@@ skipping 101 matching lines @@
     BUILD(r, WASM_F64_MUL(WASM_GET_LOCAL(0), WASM_GET_LOCAL(1)));
     r.Call(1048575.5, 2.5);
     CHECK(!r.possible_nondeterminism());
     r.Call(std::numeric_limits<double>::infinity(), 0.0);
     CHECK(r.possible_nondeterminism());
   }
 }
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8