namespace-qualify methods::as() as needed (#5644)

* namespace-qualify methods::as() as needed

As identified in https://bugs.r-project.org/show_bug.cgi?id=18540

* Update tests.Rraw

* revert

* minify diff

Author: MichaelChirico

inst/tests/tests.Rraw

@@ -12911,8 +12911,8 @@ test(1914.04, dt.s4.list, as.list(dt))  # Underlying data not identical
 # simple S4 conversion-isms work
 df = data.frame(a=sample(letters, 10), b=1:10)
 dt = as.data.table(df)
-test(1914.05, identical(as(df, 'data.table'), dt))
-test(1914.06, identical(as(dt, 'data.frame'), df))
+test(1914.05, identical(methods::as(df, 'data.table'), dt))
+test(1914.06, identical(methods::as(dt, 'data.frame'), df))
 # data.table can be used in an S4 slot
 dt <- data.table(a=sample(letters[1:3], 10, replace=TRUE), score=rnorm(10))
 dt.comp <- new("S4Composition", data=dt)

man/IDateTime.Rd

@@ -226,13 +226,13 @@ See 'Details' in \code{\link{round}} for more information.
 (d <- as.IDate("2001-01-01"))
 
 # S4 coercion also works
-identical(as.IDate("2001-01-01"), as("2001-01-01", "IDate"))
+identical(as.IDate("2001-01-01"), methods::as("2001-01-01", "IDate"))
 
 # create ITime:
 (t <- as.ITime("10:45"))
 
 # S4 coercion also works
-identical(as.ITime("10:45"), as("10:45", "ITime"))
+identical(as.ITime("10:45"), methods::as("10:45", "ITime"))
 
 (t <- as.ITime("10:45:04"))