loader: Remove updating ctx->dynamic_offset in emit_br_info (#3259)
Should not update `ctx->dynamic_offset` in emit_br_info, since the `Part e` only
sets the dst offsets, the operand stack should not be changed, e.g., the stack
operands are to be used by the opcodes followed by `br_if` opcode.
Reported in https://github.com/bytecodealliance/wasm-micro-runtime/issues/3210.