Fix static ram memory statistics for arm compiler

[maciejbocianski]

Summary of changes

Don't count ARM_LIB_HEAP in static RAM pool

stats for mbed-os-example-blinky
without fix

| Module              |     .text |   .data |       .bss |
|---------------------|-----------|---------|------------|
| [lib]\c_w.l         | 10571(+0) |  16(+0) |    348(+0) |
| [lib]\fz_wm.l       |    34(+0) |   0(+0) |      0(+0) |
| [lib]\libcppabi_w.l |    44(+0) |   0(+0) |      0(+0) |
| [lib]\m_wm.l        |    48(+0) |   0(+0) |      0(+0) |
| anon$$obj.o         |    32(+0) |   0(+0) | 197888(+0) |
| main.o              |    60(+0) |   0(+0) |      0(+0) |
| mbed-os\drivers     |   388(+0) |   0(+0) |      0(+0) |
| mbed-os\features    |    70(+0) |   0(+0) |      0(+0) |
| mbed-os\hal         |  1252(+0) |   8(+0) |    131(+0) |
| mbed-os\platform    |  4577(+0) |  64(+0) |    324(+0) |
| mbed-os\rtos        |  7768(+0) | 168(+0) |   6625(+0) |
| mbed-os\targets     | 10360(+0) |  36(+0) |    341(+0) |
| Subtotals           | 35204(+0) | 292(+0) | 205657(+0) |
Total Static RAM memory (data + bss): 205949(+0) bytes
Total Flash memory (text + data): 35496(+0) bytes

and with fix

| Module              |     .text |   .data |      .bss |
|---------------------|-----------|---------|-----------|
| [lib]\c_w.l         | 10571(+0) |  16(+0) |   348(+0) |
| [lib]\fz_wm.l       |    34(+0) |   0(+0) |     0(+0) |
| [lib]\libcppabi_w.l |    44(+0) |   0(+0) |     0(+0) |
| [lib]\m_wm.l        |    48(+0) |   0(+0) |     0(+0) |
| anon$$obj.o         |    32(+0) |   0(+0) |  2304(+0) |
| main.o              |    60(+0) |   0(+0) |     0(+0) |
| mbed-os\drivers     |   388(+0) |   0(+0) |     0(+0) |
| mbed-os\features    |    70(+0) |   0(+0) |     0(+0) |
| mbed-os\hal         |  1252(+0) |   8(+0) |   131(+0) |
| mbed-os\platform    |  4577(+0) |  64(+0) |   324(+0) |
| mbed-os\rtos        |  7768(+0) | 168(+0) |  6625(+0) |
| mbed-os\targets     | 10360(+0) |  36(+0) |   341(+0) |
| Subtotals           | 35204(+0) | 292(+0) | 10073(+0) |
Total Static RAM memory (data + bss): 10365(+0) bytes
Total Flash memory (text + data): 35496(+0) bytes

Impact of changes

Migration actions required

Documentation

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Pull request type

[X] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

[] No Tests required for this change (E.g docs only update)
[] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

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Reviewers

@bridadan @evedon @jamesbeyond

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[ciarmcom]

@maciejbocianski, thank you for your changes.
@jamesbeyond @evedon @ARMmbed/mbed-os-tools @ARMmbed/mbed-os-maintainers please review.

[JanneKiiskila]

LGTM

[jamesbeyond]

Thanks for the fixing @maciejbocianski

[0xc0170]

CI started

[mbed-ci]

Test run: SUCCESS

Summary: 11 of 11 test jobs passed
Build number : 1
Build artifacts

[JanneKiiskila]

@adbridge @0xc0170 @andypowers - it would make sense to merge his also to 5.15. branch, because memory numbers are always important in embedded system.