[IMM32] Add some candidate handlings (reactos#3799)

- Implement ImmGetCandidateListA and ImmGetCandidateListW, by using newly added ImmGetCandidateListAW function.
- Implement ImmLockClientImc and ImmUnlockClientImc functions.
- Modify imm32.spec.
- Remove #ifdef's.
CORE-11700

Author: katahiromz