Update preprocessor macros to use do-while loop

[cb1kenobi]

Several of the macros define a block scope for local variables, but that doesn't force semicolons at build time. A common pattern is to use a do-while loop which does require a semicolon while preserving the block scope. The overhead of the do-while loop is complied out anyways.

For example, take:

NAPI_STATUS_RETURN(::napi_typeof(env, argv[0], &type))

This builds just fine with the trailing semicolon, however this can lead to confusing code as we're using NAPI_* macros like they are functions.

To clean things up, we need to change macros like:

#define NAPI_STATUS_RETURN(call) \
	{ \
		napi_status status = (call); \
		if (status != napi_ok) { \
			return status; \
		} \
	}

to:

#define NAPI_STATUS_RETURN(call) \
	do { \
		napi_status status = (call); \
		if (status != napi_ok) { \
			return status; \
		} \
	} while (0)