Enable bulk memory by default (bytecodealliance#1781)

Enable bulk memory by default since it is a finished wasm spec proposal
and is enabled by default in latest wasi-sdk. Developer often encounters
"invalid section id" or "unsupported opcode" error if it isn't enabled.

build-scripts/config_common.cmake

@@ -179,11 +179,16 @@ if (WAMR_BUILD_SPEC_TEST EQUAL 1)
   add_definitions (-DWASM_ENABLE_SPEC_TEST=1)
   message ("     spec test compatible mode is on")
 endif ()
+if (NOT DEFINED WAMR_BUILD_BULK_MEMORY)
+  # Enable bulk memory by default
+  set (WAMR_BUILD_BULK_MEMORY 1)
+endif ()
 if (WAMR_BUILD_BULK_MEMORY EQUAL 1)
   add_definitions (-DWASM_ENABLE_BULK_MEMORY=1)
   message ("     Bulk memory feature enabled")
 else ()
   add_definitions (-DWASM_ENABLE_BULK_MEMORY=0)
+  message ("     Bulk memory feature disabled")
 endif ()
 if (WAMR_BUILD_SHARED_MEMORY EQUAL 1)
   add_definitions (-DWASM_ENABLE_SHARED_MEMORY=1)