Use LLVM new pass manager for wamrc (#978)

Use LLVM new pass manager for wamrc to replace the legacy pass manger,
so as to gain better performance and reduce the compilation time.
Reference links:
- https://llvm.org/docs/NewPassManager.html
- https://blog.llvm.org/posts/2021-03-26-the-new-pass-manager

And add an option to use the legacy pm mode when building wamrc:
cmake .. -DWAMR_BUILD_LLVM_LEGACY_PM=1

For JIT mode, keep it unchanged as it only runs several function passes and
using new pass manager will increase the compilation time.

And refactor the codes of applying LLVM passes.

core/iwasm/compilation/aot_llvm.h

@@ -331,9 +331,6 @@ typedef struct AOTCompContext {
     uint32 opt_level;
     uint32 size_level;
 
-    /* LLVM pass manager to optimize the JITed code */
-    LLVMPassManagerRef pass_mgr;
-
     /* LLVM floating-point rounding mode metadata */
     LLVMValueRef fp_rounding_mode;
 
@@ -469,6 +466,9 @@ aot_check_simd_compatibility(const char *arch_c_str, const char *cpu_c_str);
 void
 aot_add_expand_memory_op_pass(LLVMPassManagerRef pass);
 
+void
+aot_apply_llvm_new_pass_manager(AOTCompContext *comp_ctx);
+
 #if WASM_ENABLE_LAZY_JIT != 0
 LLVMOrcJITTargetMachineBuilderRef
 LLVMOrcJITTargetMachineBuilderCreateFromTargetMachine(LLVMTargetMachineRef TM);