Fix CI build failure by reverting --disable-thread-safety flag

The --disable-thread-safety flag was causing 'unknown type name slock_t'
compilation errors throughout PostgreSQL codebase. The original
--disable-spinlocks flag alone is sufficient for Emscripten builds.

Co-Authored-By: Dan Lynch <pyramation@gmail.com>

Author: devin-ai-integration[bot]

versions/13/patches/emscripten_disable_spinlocks.patch

@@ -5,9 +5,9 @@
 
  override PG_CONFIGURE_FLAGS += -q --without-readline --without-zlib
 +
-+# Disable spinlocks and thread safety when building with Emscripten
++# Disable spinlocks when building with Emscripten
 +ifdef EMSCRIPTEN
-+override PG_CONFIGURE_FLAGS += --disable-spinlocks --disable-thread-safety
++override PG_CONFIGURE_FLAGS += --disable-spinlocks
 +endif
 
  override TEST_CFLAGS += -I. -I./vendor -g