…errors (#2177)

### Issues:
Resolves CI failures around delocator in
#2175


### Description of changes: 
The FIPS static builds for ARM are failing CI:

```
[57%] Building ASM object crypto/fipsmodule/CMakeFiles/bcm_hashunset.dir/bcm-delocated.S.o
bcm.c: Assembler messages:
bcm.c:125130: Error: shift expression expected at operand 2 -- movi v4.4s,0xf,.Lbcm_redirector_msl,8' bcm.c:125133: Error: shift expression expected at operand 2 -- mvni v3.4s,0x1f,.Lbcm_redirector_msl,8'
bcm.c:130233: Error: shift expression expected at operand 2 -- movi v4.4s,0xf,.Lbcm_redirector_msl,8' bcm.c:130236: Error: shift expression expected at operand 2 -- mvni v3.4s,0x1f,.Lbcm_redirector_msl,8'
bcm.c:190061: Error: shift expression expected at operand 2 -- movi v4.4s,0xf,.Lbcm_redirector_msl,8' bcm.c:190064: Error: shift expression expected at operand 2 -- mvni v3.4s,0x1f,.Lbcm_redirector_msl,8'
bcm.c:206492: Error: shift expression expected at operand 2 -- movi v4.4s,0xf,.Lbcm_redirector_msl,8' bcm.c:206495: Error: shift expression expected at operand 2 -- mvni v3.4s,0x1f,.Lbcm_redirector_msl,8'
```


This was discussed back in #2096 but
not merged due to the PR being closed.


The Arm instruction has a special argument `msl`
(https://developer.arm.com/documentation/100069/0606/SIMD-Vector-Instructions/MOVI--vector-).
The delocator is intepreting `msl` as a function (or global symbol).
Since it’s not defined in the fipsmodule, it creates a jump function
`bcm_redirector_msl` outside the fipsmodule that removes a potential
relocation. The suffix of `bcm_redirector_msl` is the original token,
which matches `msl`.

We fix by adding `msl` to the list of `ARMConstantTweak` and regenerate
the `delocate.peg.go` file.

After testing this fix, I begin to see a second error in
`amazonlinux2023_clang15x_aarch_fips`:

```
[339/575] Generating bcm-delocated.S
FAILED: crypto/fipsmodule/bcm-delocated.S /codebuild/output/src1965601223/src/github.com/aws/aws-lc/test_build_dir/crypto/fipsmodule/bcm-delocated.S 
panic: Symbol reference outside of ldr instruction [recovered]
    panic: error while processing "\tldrsw\tx9, [x9, :lo12:ml_dsa_zetas+4]\n" on line 120399: "Symbol reference outside of ldr instruction"
```

It seems that `ldrsw` is not recognised as `ldr`. We already have
`ldrsw` in our code, so we extend the delocate.go to accept `ldrsw` in
addition to `ldr`.


### Call-outs:
Unblocks progress on work in the FIPS module, such as ED25519 and
ML-DSA.


By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache 2.0 license and the ISC license.