Generating tests for VLEN=128, XLEN=64, MODE=user fails

When creating the patch file, the spike goes into exception, and I get this error.
```
build/merger -stage1output out/v128x64user/tests/stage1/ -stage2output out/v128x64user/tests/stage2/ -stage2patch out/v128x64user/patches/stage2/
fatal: wrong patch generated for file vsse16_v-0.S, expected 625, got 562
```

At the end of the patch file, I see the following entries:
```
TEST_CASE(2264, t0, 0xfff8, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2265, t0, 0x0, ld t0, 0(a0); addi a0, a0, 8)
---
TEST_CASE(2266, t0, 0x1, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2267, t0, 0x0, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2268, t0, 0xf, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2269, t0, 0x0, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2270, t0, 0xfff8, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2271, t0, 0x0, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2272, t0, 0x0, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2273, t0, 0x0, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2274, t0, 0x1, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2275, t0, 0x0, ld t0, 0(a0); addi a0, a0, 8)
z 0000000000000000 ra 0000000000000000 sp 0000003ffffffb30 gp 0000000000000000
tp 0000000000000000 t0 0000000000000040 t1 0000000000000040 t2 0000000000000000
s0 0000000000000180 s1 0000000000000000 a0 0000000080008000 a1 0000000000000000
a2 0000000000000000 a3 0000000000000000 a4 0000000080008000 a5 0000000000001da0
a6 0000000000000000 a7 0000000000000000 s2 0000000000000000 s3 0000000000000000
s4 0000000000000000 s5 0000000000000000 s6 0000000000000000 s7 0000000000000000
s8 0000000000000000 s9 0000000000000000 sA 0000000000000000 sB 0000000000000000
t3 0000000000000000 t4 0000000000000000 t5 0000000000000000 t6 0000000000000000
pc 0000000080005594 va/inst 000000008000c080 sr 8000000200006620
User store segfault @ 0x000000008000c080
TEST_CASE(2276, t0, 0x0, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2277, t0, 0x0, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2278, t0, 0x0, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2279, t0, 0x0, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2280, t0, 0xfff8, ld t0, 0(a0); addi a0, a0, 8)
TEST_CASE(2281, t0, 0x0, ld t0, 0(a0); addi a0, a0, 8)
---

```

Reproduce the reported configuration with the build/merger command for VLEN=128, XLEN=64, MODE=user and inspect the generated vsse16_v-0.S patch around the reported TEST_CASE entries. Trace why the generated patch count is 562 instead of the expected 625 and why generation reaches the user store segfault; done means the command completes with matching patch counts and no exception.

Written by the indexing model from the issue text.