i#1569, i#3544 Port sample 'cbr' to AARCH64 and RISCV64.

[chenhy0106]

1. For RISCV64, conditional branch instruction of 'C' extension may not reach after adding clean call. So like X86, we add support to detect and convert compressed cbr to longer version.
2. For AARCH64 and RISCV64, a cbr may use the stolen reg and can not be mangled later as it is meta. So we check whether a cbr uses the stolen reg and replace it with a scratch reg. Now cbr works for AARCH64 and RISCV64. Still not work for ARM32 because of some bugs unrelated to cbr sample.

Issue: DynamoRIO#1569, DynamoRIO#3544