add one more section to flash with ld option --rename, only ESP8266_4MB

[MaBecker]

add rename .rodata=.irom.literal, because CCFLAG -mforce-l32 is used for ESP8266_4MB boards.

freeHeap +2064 byte

[MaBecker]

have to reverse --rename-section .rodata=.irom.literal

Some function calls cause reboot, like

• JSON.parse(undefined)
• Date.parse("Aug 9, 1995")
  . . . .

[gfwilliams]

Thanks for sorting this quickly, it's frustrating about those issues - I wonder why -mforce-l32 isn't doing its thing

[MaBecker]

.text is not 2**4 arranged like the others

Sections:
Idx Name          Size      VMA       LMA       File off  Algn
  0 .data         0000088c  3ffe8000  3ffe8000  000000e0  2**4
                  CONTENTS, ALLOC, LOAD, DATA
  1 .rodata       00002584  3ffe8890  3ffe8890  00000970  2**4
                  CONTENTS, ALLOC, LOAD, READONLY, DATA
  2 .bss          0000db20  3ffeae18  3ffeae18  00002ef8  2**4
                  ALLOC
  3 .irom0.text   000753d4  40201010  40201010  00009ea0  2**4
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
  4 .text         00006fa0  40100000  40100000  00002ef4  2**2
                  CONTENTS, ALLOC, LOAD, READONLY, CODE
```