Turn the blocks -> br_table pattern into a proper match#6

Lots of starting blocks followed by a br_table are a sign that this should actually be a proper match with different cases. At the moment it gets lowered like this: ```rust 'label0: loop { 'label1: loop { 'label2: loop { 'label3: loop { 'label4: loop { match var0.wrapping_sub(1i32) { 0 => break 'label3, 1 => break 'label2, 2 => break 'label1, _ => break 'label4, } break; } break 'label0; break; } let var1 = self.wasm_memory_load_eightBitLoadFromGBMemorySkipTraps(imports, 65298i32); return var1; break; } let var2 = self.wasm_memory_load_eightBitLoadFromGBMemorySkipTraps(imports, 65303i32); return var2; break; } let var3 = self.wasm_memory_load_eightBitLoadFromGBMemorySkipTraps(imports, 65308i32); return var3; break; } let var4 = self.wasm_memory_load_eightBitLoadFromGBMemorySkipTraps(imports, 65313i32); var4 ```