[wasm] Fix wrong SWIFT_THREADING_PACKAGE cmake cache

The actual value was accidentally placed in docstring field.

Author: kateinoigakukun

cmake/caches/Runtime-WASI-wasm32.cmake

@@ -22,7 +22,7 @@ set(SWIFT_ENABLE_EXPERIMENTAL_CONCURRENCY YES CACHE BOOL "")
 set(SWIFT_BUILD_RUNTIME_WITH_HOST_COMPILER YES CACHE BOOL "")
 
 set(SWIFT_STDLIB_SINGLE_THREADED_CONCURRENCY TRUE CACHE BOOL "")
-set(SWIFT_THREADING_PACKAGE TRUE CACHE STRING "none")
+set(SWIFT_THREADING_PACKAGE "none" CACHE STRING "")
 
 set(SWIFT_STDLIB_SUPPORTS_BACKTRACE_REPORTING FALSE CACHE BOOL "")
 set(SWIFT_STDLIB_HAS_DLADDR FALSE CACHE BOOL "")