[wasm] Turn on parallel compilation by default.

src/flag-definitions.h

 // Copyright 2012 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.
 
 // This file defines all of the flags.  It is separated into different section,
 // for Debug, Release, Logging and Profiling, etc.  To add a new flag, find the
 // correct section, and use one of the DEFINE_ macros, without a trailing ';'.
 //
 // This include does not have a guard, because it is a template-style include,
 // which can be included multiple times in different modes.  It expects to have
@@ skipping 464 matching lines @@
 DEFINE_BOOL(turbo_cache_shared_code, true, "cache context-independent code")
 DEFINE_BOOL(turbo_preserve_shared_code, false, "keep context-independent code")
 DEFINE_BOOL(turbo_escape, false, "enable escape analysis")
 DEFINE_BOOL(turbo_instruction_scheduling, false,
             "enable instruction scheduling in TurboFan")
 DEFINE_BOOL(turbo_stress_instruction_scheduling, false,
             "randomly schedule instructions to stress dependency tracking")
 
 // Flags for native WebAssembly.
 DEFINE_BOOL(expose_wasm, false, "expose WASM interface to JavaScript")
-DEFINE_INT(wasm_num_compilation_tasks, 0,
+DEFINE_INT(wasm_num_compilation_tasks, 10,
            "number of parallel compilation tasks for wasm")
 DEFINE_BOOL(trace_wasm_encoder, false, "trace encoding of wasm code")
 DEFINE_BOOL(trace_wasm_decoder, false, "trace decoding of wasm code")
 DEFINE_BOOL(trace_wasm_decode_time, false, "trace decoding time of wasm code")
 DEFINE_BOOL(trace_wasm_compiler, false, "trace compiling of wasm code")
 DEFINE_BOOL(trace_wasm_interpreter, false, "trace interpretation of wasm code")
 DEFINE_INT(trace_wasm_ast_start, 0,
            "start function for WASM AST trace (inclusive)")
 DEFINE_INT(trace_wasm_ast_end, 0, "end function for WASM AST trace (exclusive)")
 DEFINE_INT(skip_compiling_wasm_funcs, 0, "start compiling at function N")
@@ skipping 692 matching lines @@
 #undef DEFINE_ALIAS_FLOAT
 #undef DEFINE_ALIAS_ARGS
 
 #undef FLAG_MODE_DECLARE
 #undef FLAG_MODE_DEFINE
 #undef FLAG_MODE_DEFINE_DEFAULTS
 #undef FLAG_MODE_META
 #undef FLAG_MODE_DEFINE_IMPLICATIONS
 
 #undef COMMA