ssa: removes valueIDToInstruction slice

[mathetake]

goos: darwin
goarch: arm64
pkg: github.com/tetratelabs/wazero
                      │  old.txt   │             new.txt              │
                      │   sec/op   │   sec/op    vs base              │
Compilation/wazero-10   1.564 ± 0%   1.536 ± 1%  -1.78% (p=0.002 n=6)
Compilation/zig-10      3.461 ± 0%   3.421 ± 0%  -1.13% (p=0.002 n=6)
Compilation/zz-10       14.28 ± 0%   14.06 ± 1%  -1.57% (p=0.002 n=6)
geomean                 4.260        4.196       -1.49%

                      │   old.txt    │              new.txt               │
                      │     B/op     │     B/op      vs base              │
Compilation/wazero-10   286.2Mi ± 0%   283.0Mi ± 0%  -1.13% (p=0.002 n=6)
Compilation/zig-10      598.2Mi ± 0%   596.7Mi ± 0%  -0.25% (p=0.002 n=6)
Compilation/zz-10       538.0Mi ± 0%   536.5Mi ± 0%  -0.28% (p=0.002 n=6)
geomean                 451.6Mi        449.1Mi       -0.55%

                      │   old.txt   │              new.txt              │
                      │  allocs/op  │  allocs/op   vs base              │
Compilation/wazero-10   485.5k ± 0%   485.3k ± 0%       ~ (p=0.394 n=6)
Compilation/zig-10      275.5k ± 0%   275.5k ± 0%       ~ (p=0.937 n=6)
Compilation/zz-10       627.0k ± 0%   627.0k ± 0%       ~ (p=0.589 n=6)
geomean                 437.7k        437.7k       -0.01%

#2182