[wasm][testing] Fix definition of kSig_f_v

There is a clear mistake of using kWasmF64 instead of kWasmF32.

R=ahaas@chromium.org

Change-Id: I638d568b3736fdb8417f17bcd04d17268a45b965
Reviewed-on: https://chromium-review.googlesource.com/939178Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51595}

test/mjsunit/wasm/wasm-constants.js

@@ -114,7 +114,7 @@ let kSig_i_dd = makeSig([kWasmF64, kWasmF64], [kWasmI32]);
 let kSig_v_v = makeSig([], []);
 let kSig_i_v = makeSig([], [kWasmI32]);
 let kSig_l_v = makeSig([], [kWasmI64]);
-let kSig_f_v = makeSig([], [kWasmF64]);
+let kSig_f_v = makeSig([], [kWasmF32]);
 let kSig_d_v = makeSig([], [kWasmF64]);
 let kSig_v_i = makeSig([kWasmI32], []);
 let kSig_v_ii = makeSig([kWasmI32, kWasmI32], []);