[R] Handling unexpected input to time64() et al

[asfimport]

> time64()
Error in Time64__initialize(unit) : 
  argument "unit" is missing, with no default
> time64("ms")
Error in Time64__initialize(unit) : 
  Not compatible with requested type: [type=character; target=integer].
> time64(1)
WARNING: Logging before InitGoogleLogging() is written to STDERR
F0826 11:13:34.657388 162407872 type.cc:234]  Check failed: unit == TimeUnit::MICRO || unit == TimeUnit::NANO Must be microseconds or nanoseconds
*** Check failure stack trace: ***
Abort trap: 6

> time64(1L)
WARNING: Logging before InitGoogleLogging() is written to STDERR
F0826 11:14:09.445202 251229632 type.cc:234]  Check failed: unit == TimeUnit::MICRO || unit == TimeUnit::NANO Must be microseconds or nanoseconds
*** Check failure stack trace: ***
Abort trap: 6

> time64("MILLI")
Error in Time64__initialize(unit) : 
  Not compatible with requested type: [type=character; target=integer].
> time64(TimeUnit$MILLI)
WARNING: Logging before InitGoogleLogging() is written to STDERR
F0826 11:15:12.047847 361547200 type.cc:234]  Check failed: unit == TimeUnit::MICRO || unit == TimeUnit::NANO Must be microseconds or nanoseconds
*** Check failure stack trace: ***
Abort trap: 6

Reporter: Neal Richardson / @nealrichardson
Assignee: Neal Richardson / @nealrichardson

PRs and other links:

• GitHub Pull Request #5201

_{Note: This issue was originally created as ARROW-6364. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
Issue resolved by pull request 5201
#5201