Rename thread_spawn to thread-spawn in wat tests

cf.
WebAssembly#26
WebAssembly/wasi-libc#387

Author: yamt

test/testsuite/wasi_threads_exit_main_block.wat

@@ -6,7 +6,7 @@
 
 (module
   (memory (export "memory") (import "foo" "bar") 1 1 shared)
-  (func $thread_spawn (import "wasi" "thread_spawn") (param i32) (result i32))
+  (func $thread_spawn (import "wasi" "thread-spawn") (param i32) (result i32))
   (func $proc_exit (import "wasi_snapshot_preview1" "proc_exit") (param i32))
   (func (export "wasi_thread_start") (param i32 i32)
     ;; infinite wait

test/testsuite/wasi_threads_exit_main_busy.wat

@@ -6,7 +6,7 @@
 
 (module
   (memory (export "memory") (import "foo" "bar") 1 1 shared)
-  (func $thread_spawn (import "wasi" "thread_spawn") (param i32) (result i32))
+  (func $thread_spawn (import "wasi" "thread-spawn") (param i32) (result i32))
   (func $proc_exit (import "wasi_snapshot_preview1" "proc_exit") (param i32))
   (func (export "wasi_thread_start") (param i32 i32)
     ;; infinite loop

test/testsuite/wasi_threads_exit_main_wasi.wat

@@ -9,7 +9,7 @@
 
 (module
   (memory (export "memory") (import "foo" "bar") 1 1 shared)
-  (func $thread_spawn (import "wasi" "thread_spawn") (param i32) (result i32))
+  (func $thread_spawn (import "wasi" "thread-spawn") (param i32) (result i32))
   (func $proc_exit (import "wasi_snapshot_preview1" "proc_exit") (param i32))
   (func $poll_oneoff (import "wasi_snapshot_preview1" "poll_oneoff") (param i32 i32 i32 i32) (result i32))
   (func (export "wasi_thread_start") (param i32 i32)

test/testsuite/wasi_threads_exit_nonmain_block.wat

@@ -6,7 +6,7 @@
 
 (module
   (memory (export "memory") (import "foo" "bar") 1 1 shared)
-  (func $thread_spawn (import "wasi" "thread_spawn") (param i32) (result i32))
+  (func $thread_spawn (import "wasi" "thread-spawn") (param i32) (result i32))
   (func $proc_exit (import "wasi_snapshot_preview1" "proc_exit") (param i32))
   (func (export "wasi_thread_start") (param i32 i32)
     ;; wait 500ms to ensure the other thread block

test/testsuite/wasi_threads_exit_nonmain_busy.wat

@@ -6,7 +6,7 @@
 
 (module
   (memory (export "memory") (import "foo" "bar") 1 1 shared)
-  (func $thread_spawn (import "wasi" "thread_spawn") (param i32) (result i32))
+  (func $thread_spawn (import "wasi" "thread-spawn") (param i32) (result i32))
   (func $proc_exit (import "wasi_snapshot_preview1" "proc_exit") (param i32))
   (func (export "wasi_thread_start") (param i32 i32)
     ;; wait 500ms to ensure the other thread to enter the busy loop

test/testsuite/wasi_threads_exit_nonmain_wasi.wat

@@ -9,7 +9,7 @@
 
 (module
   (memory (export "memory") (import "foo" "bar") 1 1 shared)
-  (func $thread_spawn (import "wasi" "thread_spawn") (param i32) (result i32))
+  (func $thread_spawn (import "wasi" "thread-spawn") (param i32) (result i32))
   (func $proc_exit (import "wasi_snapshot_preview1" "proc_exit") (param i32))
   (func $poll_oneoff (import "wasi_snapshot_preview1" "poll_oneoff") (param i32 i32 i32 i32) (result i32))
   (func (export "wasi_thread_start") (param i32 i32)

test/testsuite/wasi_threads_spawn.wat

@@ -7,7 +7,7 @@
 
 (module
   (memory (export "memory") (import "foo" "bar") 1 1 shared)
-  (func $thread_spawn (import "wasi" "thread_spawn") (param i32) (result i32))
+  (func $thread_spawn (import "wasi" "thread-spawn") (param i32) (result i32))
   (func $proc_exit (import "wasi_snapshot_preview1" "proc_exit") (param i32))
   (func (export "wasi_thread_start") (param $tid i32) (param $user_arg i32)
     ;; store tid