Fix two errors in asm emit

src/assembler.ts

@@ -619,7 +619,6 @@ export class File {
                 this.directiveError("invalid .float16")
             const n = float16toUInt16(v)
             this.emitShort(n & 0xffff)
-            this.emitShort((n >> 16) & 0xffff)
         })
     }
 

src/ir.ts

@@ -131,7 +131,7 @@ function addFloat16(mi: ModelInfo, v: number) {
 export function alignWeights(mi: ModelInfo) {
     while (mi.weightPtr & 3)
         addParamBytes(mi, [0])
-    mi.weightAsm += ".align 4\n"
+    mi.weightAsm += ".balign 4\n"
 }
 
 export function addWeight(mi: ModelInfo, v: number) {