RISCV: Fix operand detection (REAL/ALIAS)

[slate5]

Your checklist for this pull request

• I've documented or updated the documentation of every API function and struct this PR changes.
• I've added tests that prove my fix is effective or that my feature works (if possible)

Detailed description

Fixing issue #2896

Also adding a new expected field (uses_alias_details) to cstest.

Test plan

cstool -d riscv64 67800000
 0  67 80 00 00  ret	
	ID: 31 (jalr)
	Is alias: 1698 (ret) with ALIAS operand set

	Groups: jump 

cstool -dr riscv64 67800000
 0  67 80 00 00  ret	
	ID: 31 (jalr)
	Is alias: 1698 (ret) with REAL operand set
	op_count: 3
		operands[0].type: REG = zero
		operands[0].access: WRITE
		operands[1].type: REG = ra
		operands[1].access: READ
		operands[2].type: IMM = 0x0
		operands[2].access: READ

	Groups: ret 

Closing issues

closes #2896

[Rot127]

Thanks for the test extension!

[moste00]

LGTM