jscript: Fixed some Coverity issues.

dlls/jscript/array.c

@@ -325,7 +325,7 @@ static HRESULT array_join(script_ctx_t *ctx, jsdisp_t *array, DWORD length, cons
     TRACE("= %s\n", debugstr_jsstr(ret));
 
     if(r)
-        *r = ret ? jsval_string(ret) : jsval_string(jsstr_empty());
+        *r = jsval_string(ret);
     else
         jsstr_release(ret);
     return S_OK;

dlls/jscript/compile.c

@@ -1395,6 +1395,8 @@ static HRESULT compile_continue_statement(compiler_ctx_t *ctx, branch_statement_
             WARN("Label is not a loop\n");
             return JS_E_INVALID_CONTINUE;
         }
+
+        assert(pop_ctx != NULL);
     }else {
         for(pop_ctx = ctx->stat_ctx; pop_ctx; pop_ctx = pop_ctx->next) {
             if(pop_ctx->continue_label)

dlls/jscript/dispex.c

@@ -454,6 +454,7 @@ static HRESULT prop_put(jsdisp_t *This, dispex_prop_t *prop, jsval_t val, IServi
             vdisp_release(&vthis);
             return hres;
         }
+        /* fall through */
     case PROP_PROTREF:
         prop->type = PROP_JSVAL;
         prop->flags = PROPF_ENUM;