Improve ecma_string_t descriptor (#3016)

This patch introduces several changes conntect to ecma-strings:
 - Extend the size of the reference counter to 28 bytes from 13
 - Extend the size of the string hash to 32 bytes from 16 to use the extact FNV-1a hash
 - Introduce ECMA_STATIC_STRING_FLAG to reduce the number of string ref/derefs for static strings.
 - Introduce ECMA_STRING_CONTAINER_ASCII_STRING to store run-time allocated ASCII strings more efficiently
 - Remove ECMA_STRING_CONTAINER_LIT_NUMBER to half the storage size of the parsing time allocated floating point numbers
 - Rework the global number storage, to store only the floating point numbers
 - Optimize the lookup in the global number/string/symbol tables via reduce the number of NULL checks during decompressing the next element pointers
 - Reduce the code duplication in ecma_concat_ecma_strings and ecma_append_chars_to_string
 - Improve ecma_string_get_char with optional arguments to make it more reusable.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

jerry-core/lit/lit-globals.h

@@ -121,16 +121,11 @@ typedef uint32_t lit_code_point_t;
 /**
  * ECMA string hash
  */
-typedef uint16_t lit_string_hash_t;
+typedef uint32_t lit_string_hash_t;
 
 /**
- * Maximum value of ECMA string hash + 1
- *
- * Note:
- *   On ARM, this constant can be encoded as an immediate value
- *   while 0xffffu cannot be. Hence using this constant reduces
- *   binary size and improves performance.
+ * Maximum value of ECMA string hash
  */
-#define LIT_STRING_HASH_LIMIT 0x10000u
+#define LIT_STRING_HASH_LIMIT UINT32_MAX
 
 #endif /* !LIT_GLOBALS_H */