Fix crash when assigning to bool class fields (#95)

With `Type.bool`, size is 1, so dividing by 8 isn't the right way to convert to byteSize. Instead, we need to use the `byteSize` property that does the proper ceiling division.

tests/compiler/class-with-boolean-field.optimized.wat

@@ -0,0 +1,16 @@
+(module
+ (type $i (func (result i32)))
+ (memory $0 1)
+ (export "test" (func $class-with-boolean-field/test))
+ (export "memory" (memory $0))
+ (func $class-with-boolean-field/test (; 0 ;) (type $i) (result i32)
+  (local $0 i32)
+  (i32.store8
+   (get_local $0)
+   (i32.const 1)
+  )
+  (i32.load8_u
+   (get_local $0)
+  )
+ )
+)

tests/compiler/class-with-boolean-field.ts

@@ -0,0 +1,9 @@
+class A {
+  boolValue: bool;
+}
+
+export function test(): bool {
+  let a: A;
+  a.boolValue = true;
+  return a.boolValue;
+}

tests/compiler/class-with-boolean-field.untouched.wat

@@ -0,0 +1,20 @@
+(module
+ (type $i (func (result i32)))
+ (global $HEAP_BASE i32 (i32.const 4))
+ (memory $0 1)
+ (export "test" (func $class-with-boolean-field/test))
+ (export "memory" (memory $0))
+ (func $class-with-boolean-field/test (; 0 ;) (type $i) (result i32)
+  (local $0 i32)
+  (nop)
+  (i32.store8
+   (get_local $0)
+   (i32.const 1)
+  )
+  (return
+   (i32.load8_u
+    (get_local $0)
+   )
+  )
+ )
+)