ci: merges spectests into normal make test

[mathetake]

Previously, only specification tests are run separately
from the rest of the tests just to run in a separate
GHA workflow (named spectest) to have a badge to brag.
This used to unnecessarily use CI resources, and no need to
do so anymore.

[mathetake]

--- FAIL: TestInterpreter (10.79s)
    --- FAIL: TestInterpreter/simd_i32x4_dot_i16x8.wast (0.00s)
        --- FAIL: TestInterpreter/simd_i32x4_dot_i16x8.wast/assert_return/line:22 (0.00s)
            require.go:331: expected true, but was false: simd_i32x4_dot_i16x8.wast:22 assert_return invoke i32x4.dot_i16x8_s ([{type: v128[lane=i16], value: 1,1,1,1,1,1,1,1} {type: v128[lane=i16], value: 65535,65535,65535,65535,65535,65535,65535,65535}])
                	have [i32x4(0xfffffffe, 0xffffffff, 0xfffffffe, 0xffffffff)]
                	want [i32x4(0xfffffffe, 0xfffffffe, 0xfffffffe, 0xfffffffe)]
                /Users/runner/work/wazero/wazero/internal/integration_test/spectest/spectest.go:428
        --- FAIL: TestInterpreter/simd_i32x4_dot_i16x8.wast/assert_return/line:49 (0.00s)
            require.go:331: expected true, but was false: simd_i32x4_dot_i16x8.wast:49 assert_return invoke i32x4.dot_i16x8_s ([{type: v128[lane=i16], value: 32768,32768,32768,32768,32768,32768,32768,32768} {type: v128[lane=i16], value: 1,1,1,1,1,1,1,1}])
                	have [i32x4(0xffff0000, 0xffffffff, 0xffff0000, 0xffffffff)]
                	want [i32x4(0xffff0000, 0xffff0000, 0xffff0000, 0xffff0000)]
                /Users/runner/work/wazero/wazero/internal/integration_test/spectest/spectest.go:428
        --- FAIL: TestInterpreter/simd_i32x4_dot_i16x8.wast/assert_return/line:[64](https://github.com/tetratelabs/wazero/actions/runs/9699253607/job/26767777650?pr=2273#step:5:65) (0.00s)
            require.go:331: expected true, but was false: simd_i32x4_dot_i16x8.wast:64 assert_return invoke i32x4.dot_i16x8_s ([{type: v128[lane=i16], value: 32768,32768,32768,32768,32768,32768,32768,32768} {type: v128[lane=i16], value: 32768,32768,32768,32768,32768,32768,32768,32768}])
                	have [i32x4(0x80000000, 0xffffffff, 0x80000000, 0xffffffff)]
                	want [i32x4(0x80000000, 0x80000000, 0x80000000, 0x80000000)]
                /Users/runner/work/wazero/wazero/internal/integration_test/spectest/spectest.go:428
        --- FAIL: TestInterpreter/simd_i32x4_dot_i16x8.wast/assert_return/line:73 (0.00s)
            require.go:331: expected true, but was false: simd_i32x4_dot_i16x8.wast:73 assert_return invoke i32x4.dot_i16x8_s ([{type: v128[lane=i16], value: [65](https://github.com/tetratelabs/wazero/actions/runs/9699253607/job/26767777650?pr=2273#step:5:66)535,65535,65535,65535,65535,65535,65535,65535} {type: v128[lane=i16], value: 1,1,1,1,1,1,1,1}])
                	have [i32x4(0xfffffffe, 0xffffffff, 0xfffffffe, 0xffffffff)]
                	want [i32x4(0xfffffffe, 0xfffffffe, 0xfffffffe, 0xfffffffe)]
                /Users/runner/work/wazero/wazero/internal/integration_test/spectest/spectest.go:428
        --- FAIL: TestInterpreter/simd_i32x4_dot_i16x8.wast/assert_return/line:79 (0.00s)
            require.go:331: expected true, but was false: simd_i32x4_dot_i16x8.wast:79 assert_return invoke i32x4.dot_i16x8_s ([{type: v128[lane=i16], value: 65535,65535,65535,65535,65535,65535,65535,65535} {type: v128[lane=i16], value: 327[67](https://github.com/tetratelabs/wazero/actions/runs/9699253607/job/26767777650?pr=2273#step:5:68),32767,32767,32767,32767,32767,32767,32767}])
                	have [i32x4(0xffff0002, 0xffffffff, 0xffff0002, 0xffffffff)]
                	want [i32x4(0xffff0002, 0xffff0002, 0xffff0002, 0xffff0002)]
                /Users/runner/work/wazero/wazero/internal/integration_test/spectest/spectest.go:428

wat

[mathetake]

golang/go#68227