common/json_parse_simple: make convenience functions inline

json_tok_streq(…) and json_get_member(…) are convenience wrappers for
json_tok_strneq(…) and json_get_membern(…) respectively. Unfortunately, using
them incurs a performance penalty in the common case where they are called with
a string literal argument because the compiler is unable to substitute a
compile-time constant in place of the buried call to strlen(…).

For example,

	json_get_member(buf, tok, "example");

…will have worse performance than…

	json_get_membern(buf, tok, "example", strlen("example"));

…because the former is forced to scan over "example" at run-time to count its
length whereas the latter is able to elide the strlen(…) call at compile time.

Hoist these convenience functions up into common/json_parse_simple.h and mark
them as inline so that the compiler can elide the strlen(…) call in the common
case of calling these functions with a string literal argument.

Changelog-None

common/json_parse_simple.c

@@ -33,11 +33,6 @@ bool json_tok_strneq(const char *buffer, const jsmntok_t *tok,
 	return memeq(buffer + tok->start, tok->end - tok->start, str, len);
 }
 
-bool json_tok_streq(const char *buffer, const jsmntok_t *tok, const char *str)
-{
-	return json_tok_strneq(buffer, tok, str, strlen(str));
-}
-
 bool json_tok_startswith(const char *buffer, const jsmntok_t *tok,
 			 const char *prefix)
 {
@@ -217,12 +212,6 @@ const jsmntok_t *json_get_membern(const char *buffer,
 	return NULL;
 }
 
-const jsmntok_t *json_get_member(const char *buffer, const jsmntok_t tok[],
-				 const char *label)
-{
-	return json_get_membern(buffer, tok, label, strlen(label));
-}
-
 const jsmntok_t *json_get_arr(const jsmntok_t tok[], size_t index)
 {
 	const jsmntok_t *t;