Fix logging related issues (#4971)

PR #4907 moved the log level into the engine context, however this caused
issues with logging without the engine being initialized. This commit
reverts the log level to be a static variable.

This commit also implements missing format specifiers for jerry_log.

JerryScript-DCO-1.0-Signed-off-by: Dániel Bátyai dbatyai@inf.u-szeged.hu

jerry-core/jcontext/jcontext.h

@@ -169,7 +169,6 @@ struct jerry_context_t
   uint32_t lit_magic_string_ex_count; /**< external magic strings count */
   uint32_t jerry_init_flags; /**< run-time configuration flags */
   uint32_t status_flags; /**< run-time flags (the top 8 bits are used for passing class parsing options) */
-  jerry_log_level_t log_level; /**< current log level */
 
 #if (JERRY_GC_MARK_LIMIT != 0)
   uint32_t ecma_gc_mark_recursion_limit; /**< GC mark recursion limit */