Fix IA32 compilation with common IRQ entry disabled

[Ryzee119]

Fix IA32 compilation with common IRQ entry disabled

Description

This change fixes compilation errors when using IA32 port when configUSE_COMMON_INTERRUPT_ENTRY_POINT is set to 0.
The follow compilation error is generated:

portable/GCC/IA32_flat/port.c:669:14: error: use of undeclared identifier 'xInterruptHandlerTable'
  669 |     else if( xInterruptHandlerTable[ ulVectorNumber ] != NULL )

Test Steps

• Modify template_configuration/FreeRTOSConfig.h as follows:

-#define configMAX_API_CALL_INTERRUPT_PRIORITY    0
+#define configMAX_API_CALL_INTERRUPT_PRIORITY    2  //Just to pass IA32 port.c checks

• Compiling will generate the above error.

gcc -m32 -march=pentium -c -o port.o portable/GCC/IA32_flat/port.c -DconfigISR_STACK_SIZE=256 -DconfigUSE_COMMON_INTERRUPT_ENTRY_POINT=0 -Iexamples/template_configuration -Iinclude -Iportable/GCC/IA32_flat

Checklist:

• I have tested my changes. No regression in existing tests.
• I have modified and/or added unit-tests to cover the code changes in this Pull Request.

Related Issue

N/A

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