Fix the MSVC build.

In LiftoffCompiler::EmitTypeConversion() there is a DCHECK_EQ() where
one argument is implicitly converted to bool. This confuses MSVC, which
causes it to think the two arguments to DCHECK_EQ() do not have the same
type. Fix this with an explicit bool conversion!!

This does not affect the "v8_win64_msvc_compile_rel" bot, presumably
because it is a release bot with DCHECKs turned off.

Change-Id: I602ddae7a970e17388730e895eafd4ec78de7602
Reviewed-on: https://chromium-review.googlesource.com/1187702Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55381}

src/wasm/baseline/liftoff-compiler.cc

@@ -585,7 +585,7 @@ class LiftoffCompiler {
     LiftoffRegister src = __ PopToRegister();
     LiftoffRegister dst = src_rc == dst_rc ? __ GetUnusedRegister(dst_rc, {src})
                                            : __ GetUnusedRegister(dst_rc);
-    DCHECK_EQ(can_trap, trap_position > 0);
+    DCHECK_EQ(!!can_trap, trap_position > 0);
     Label* trap = can_trap ? AddOutOfLineTrap(
                                  trap_position,
                                  WasmCode::kThrowWasmTrapFloatUnrepresentable)