argv_buf on-stack array sizes might have a room to improve

[yamt]

we have the argv_buf on-stack array pattern in our code base.
the sizes of the arrays seem a bit arbitrary.

core/iwasm/common/wasm_c_api.c:    uint32 argv_buf[32] = { 0 }, *argv = argv_buf;
core/iwasm/common/wasm_runtime_common.c:    uint32 argc, argv_buf[16] = { 0 }, *argv = argv_buf, cell_num, module_type;
core/iwasm/common/wasm_runtime_common.c:    uint64 argv_buf[16] = { 0 }, *argv1 = argv_buf, *argv_dst, size, arg_i64;
core/iwasm/common/wasm_runtime_common.c:    uint32 argv_buf[32], *argv1 = argv_buf, *ints, *stacks, size;
core/iwasm/common/wasm_runtime_common.c:    uint32 argv_buf[32], *argv1 = argv_buf, argc1, i, j = 0;
core/iwasm/common/wasm_runtime_common.c:    uint64 argv_buf[32] = { 0 }, *argv1 = argv_buf, *ints, *stacks, size,

reference:
#3314 (comment)