### What changes were proposed in this pull request?
This PR proposes:
1. Use `is.data.frame` to check if it is a DataFrame.
2. to install Arrow and test Arrow optimization in AppVeyor build. We're currently not testing this in CI.
### Why are the changes needed?
1. To support SparkR with Arrow 0.14
2. To check if there's any regression and if it works correctly.
### Does this PR introduce any user-facing change?
```r
df <- createDataFrame(mtcars)
collect(dapply(df, function(rdf) { data.frame(rdf$gear + 1) }, structType("gear double")))
```
**Before:**
```
Error in readBin(con, raw(), as.integer(dataLen), endian = "big") :
invalid 'n' argument
```
**After:**
```
gear
1 5
2 5
3 5
4 4
5 4
6 4
7 4
8 5
9 5
...
```
### How was this patch tested?
AppVeyor
Closes#25993 from HyukjinKwon/arrow-r-appveyor.
Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
0f48aafab8