Go: Convert models for variadic functions to use models-as-data

[owen-mc]

These were not converted when most of the rest of the models were converted in #12750 because at the time flow didn't work through variadic parameters when using models-as-data. That was fixed in #11732.

When a class existed just function modeling and it was public instead of private I have deprecated it and removed the inheritance from TaintTracking::FunctionModel.

[github-actions]

⚠️ The head of this PR and the base branch were compared for differences in the framework coverage reports. The generated reports are available in the artifacts of this workflow run. The differences will be picked up by the nightly job after the PR gets merged.

Click to show differences in coverage

go

Generated file changes for go

• Changes to framework-coverage-go.rst:

-    `Standard library <https://pkg.go.dev/std>`_,"````, ``archive/*``, ``bufio``, ``bytes``, ``cmp``, ``compress/*``, ``container/*``, ``context``, ``crypto``, ``crypto/*``, ``database/*``, ``debug/*``, ``embed``, ``encoding``, ``encoding/*``, ``errors``, ``expvar``, ``flag``, ``fmt``, ``go/*``, ``hash``, ``hash/*``, ``html``, ``html/*``, ``image``, ``image/*``, ``index/*``, ``io``, ``io/*``, ``log``, ``log/*``, ``maps``, ``math``, ``math/*``, ``mime``, ``mime/*``, ``net``, ``net/*``, ``os``, ``os/*``, ``path``, ``path/*``, ``plugin``, ``reflect``, ``reflect/*``, ``regexp``, ``regexp/*``, ``slices``, ``sort``, ``strconv``, ``strings``, ``sync``, ``sync/*``, ``syscall``, ``syscall/*``, ``testing``, ``testing/*``, ``text/*``, ``time``, ``time/*``, ``unicode``, ``unicode/*``, ``unsafe``",8,581,
+    `Standard library <https://pkg.go.dev/std>`_,"````, ``archive/*``, ``bufio``, ``bytes``, ``cmp``, ``compress/*``, ``container/*``, ``context``, ``crypto``, ``crypto/*``, ``database/*``, ``debug/*``, ``embed``, ``encoding``, ``encoding/*``, ``errors``, ``expvar``, ``flag``, ``fmt``, ``go/*``, ``hash``, ``hash/*``, ``html``, ``html/*``, ``image``, ``image/*``, ``index/*``, ``io``, ``io/*``, ``log``, ``log/*``, ``maps``, ``math``, ``math/*``, ``mime``, ``mime/*``, ``net``, ``net/*``, ``os``, ``os/*``, ``path``, ``path/*``, ``plugin``, ``reflect``, ``reflect/*``, ``regexp``, ``regexp/*``, ``slices``, ``sort``, ``strconv``, ``strings``, ``sync``, ``sync/*``, ``syscall``, ``syscall/*``, ``testing``, ``testing/*``, ``text/*``, ``time``, ``time/*``, ``unicode``, ``unicode/*``, ``unsafe``",8,626,
-    `beego <https://beego.me/>`_,"``github.com/astaxie/beego*``, ``github.com/beego/beego*``",,42,
+    `beego <https://beego.me/>`_,"``github.com/astaxie/beego*``, ``github.com/beego/beego*``",,44,
-    `zap <https://go.uber.org/zap>`_,``go.uber.org/zap*``,,11,
+    `zap <https://go.uber.org/zap>`_,``go.uber.org/zap*``,,12,
-    Totals,,20,874,24
+    Totals,,20,922,24

• Changes to framework-coverage-go.csv:

- database/sql,,,7,,,,7,
+ database/sql,,,9,,,,9,
- errors,,,3,,,,3,
+ errors,,,4,,,,4,
- fmt,,,16,,,,16,
+ fmt,,,28,,,,28,
- github.com/astaxie/beego/utils,,,13,,,,13,
+ github.com/astaxie/beego/utils,,,14,,,,14,
- github.com/beego/beego/core/utils,,,13,,,,13,
+ github.com/beego/beego/core/utils,,,14,,,,14,
- go.uber.org/zap,,,11,,,,11,
+ go.uber.org/zap,,,12,,,,12,
- html/template,,,6,,,,6,
+ html/template,,,9,,,,9,
- io,,,19,,,,19,
+ io,,,20,,,,20,
- log,,,3,,,,3,
+ log,,,15,,,,15,
- net/textproto,,,19,,,,19,
+ net/textproto,,,21,,,,21,
- net/url,,,23,,,,23,
+ net/url,,,27,,,,27,
- path,,,5,,,,5,
+ path,,,6,,,,6,
- path/filepath,,,13,,,,13,
+ path/filepath,,,14,,,,14,
- reflect,,,37,,,,37,
+ reflect,,,39,,,,39,
- strings,,,34,,,,34,
+ strings,,,35,,,,35,
- text/template,,,6,,,,6,
+ text/template,,,9,,,,9,

[owen-mc]

Converting these models to models-as-data has highlighted a few bugs. This PR shouldn't be merged until they are fixed, so I've converted it to a draft.

• There currently isn't any flow out through an implicit varargs parameter. Stdlib functions like fmt.SScan require this functionality.
• Some barrier guard definitions use localTaintStep to detect taint flow, but it doesn't work flow through an implicit varargs slice.