add validation of dynamic_offset

[Septa2112]

In Fast-Interpreter mode, wasm_loader_pop_frame_offset does not validate dynamic_offset before performing calculations. This can lead to an potential unsigned integer underflow in certain cases, for example when cell_num_to_pop exceeds dynamic_offset:

wasm-micro-runtime/core/iwasm/interpreter/wasm_loader.c

Line 9869 in cbb6d03

ctx->dynamic_offset -= cell_num_to_pop;

This patch adds a validation step for dynamic_offset to prevent such cases and improve code robustness.