This is first in a series of patches to fix PR25722.
This change adds a new constant pool kind to ARMOperand. When parsing the operand for =immediate we create an instance of this operand rather than creating a constant pool entry and rewriting the operand.
As the new operand kind is only created for ldr rt,= we can make ldr rt,= an explicit pseudo instruction in ARM, Thumb and Thumb2
The pseudo instruction is expanded in processInstruction(). This creates the constant pool and transforms the pseudo instruction into a pc-relative ldr to the constant pool.
There are no functional changes and no modifications needed to existing tests.