hal/ia32: fix edx restoration in exceptions

[badochov]

JIRA: RTOS-954

Description

Fix of error introduced in #609.

Motivation and Context

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (refactoring, style fixes, git/CI config, submodule management, no code logic changes)

How Has This Been Tested?

• Already covered by automatic testing.
• New test added: (add PR link here).
• Tested by hand on: ia32

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing linter checks and tests passed.
• My changes generate no new compilation warnings for any of the targets.

Special treatment

• This PR needs additional PRs to work (list the PRs, preferably in merge-order).
• I will merge this PR by myself when appropriate.

[badochov]

I found this using shared libs on C++. There there's a combination of first FPU usage causing exc7 followed by an operation using %edx.

It would be nice to have some tests testing if syscalls only alter the %eax or equivalent in other architectures and exceptions do not alter any register (unless on some arch they are supposed to).

[github-actions]

Unit Test Results

7 787 tests  ±0   7 069 ✅ ±0   40m 56s ⏱️ -10s
  461 suites ±0     718 💤 ±0 
    1 files   ±0       0 ❌ ±0 

Results for commit 8f37dbd. ± Comparison against base commit a6de825.

[badochov]

Closed as merged in !613