[JITLink][RISCV] fix the extractBits behavior and add R_RISCV_JAL relocation.

This patch supports the R_RISCV_JAL relocation.
Moreover, it will fix the extractBits function's behavior as it extracts Size + 1 bits.
In the test ELF_jal.s:
Before:
```
Hi: 4294836480
extractBits(Hi, 12, 8): 480
```
After:
```
Hi: 4294836480
extractBits(Hi, 12, 8): 224
```

Reviewed By: StephenFan

Differential Revision: https://reviews.llvm.org/D117975