cgen: fix auto eq for fixed array

[felipensp]

Fix vlib/json/tests/json_generic_array_test.v failing test

Fix #23149

_{Huly®: V_0.6-21606}

[spytheman]

It still fails one of the sanitized checks for:

#0 09:56:27 ^ master /v/oo>./v -keepc -cg -cc clang-18 -cflags -fsanitize=memory vlib/json/tests/json_generic_array_test.v
Uninitialized bytes in MemcmpInterceptorCommon at offset 4 inside [0x7fffffffbe18, 32)
==2255226==WARNING: MemorySanitizer: use-of-uninitialized-value
/usr/bin/llvm-symbolizer-18: /usr/local/lib/libcurl.so.4: no version information available (required by /usr/bin/llvm-symbolizer-18)
    #0 0x5555555d3625 in memcmp (/space/v/oo/vlib/json/tests/json_generic_array_test+0x7f625) (BuildId: eef1284e3cc1c46b79b037fa8f91e8c96d6db0ed)
    #1 0x5555556838ba in _option_Array_fixed_int_1_arr_eq /tmp/v_1000/json_generic_array_test.tmp.c:4218:7
    #2 0x5555556840ea in main__DocumentFindFilter_T_int_struct_eq /tmp/v_1000/json_generic_array_test.tmp.c:4232:77
    #3 0x55555570f761 in main__test_int /tmp/v_1000/json_generic_array_test.tmp.c:10751:6
    #4 0x555555714a94 in main /tmp/v_1000/json_generic_array_test.tmp.c:10930:3
    #5 0x7ffff7be8082 in __libc_start_main /build/glibc-LcI20x/glibc-2.31/csu/../csu/libc-start.c:308:16
    #6 0x55555559466d in _start (/space/v/oo/vlib/json/tests/json_generic_array_test+0x4066d) (BuildId: eef1284e3cc1c46b79b037fa8f91e8c96d6db0ed)

SUMMARY: MemorySanitizer: use-of-uninitialized-value (/space/v/oo/vlib/json/tests/json_generic_array_test+0x7f625) (BuildId: eef1284e3cc1c46b79b037fa8f91e8c96d6db0ed) in memcmp
Exiting
#1 09:57:10 ^ master /v/oo>

[spytheman]

Excellent work.

I think it will pass this time all sanitized CI jobs.

[spytheman]

vlib/v/tests/assert_alias_array_test.v is missing (it was reverted on master)

[felipensp]

vlib/v/tests/assert_alias_array_test.v is missing (it was reverted on master)

Oh thanks.