misc: disable goconst linter, remove nolint in internal/compiler (#3585)

* golangci-lint: remove goconst linter

We've debated turning it to 10, or removing it alltogether; landed
at the fact that if the number of occurrences really is 10+, it'll
be noted in code review anyways.

* internal/compiler/wasm: more selectively disable deadcode/varcheck linter

Signed-off-by: Stephan Renatus <stephan.renatus@gmail.com>

.golangci.yaml

@@ -14,9 +14,7 @@ linters:
     - errcheck
     - govet
     - ineffassign
-#    - golint # deprecated and no longer supported
     - revive # replacement for golint
-    - goconst
     - gofmt
     - goimports
     - unused

internal/compiler/wasm/wasm.go

@@ -3,7 +3,6 @@
 // license that can be found in the LICENSE file.
 
 // Package wasm contains an IR->WASM compiler backend.
-// nolint: deadcode,varcheck // Package in development (2021).
 package wasm
 
 import (
@@ -32,6 +31,7 @@ const (
 	opaWasmABIMinorVersionVar = "opa_wasm_abi_minor_version"
 )
 
+// nolint: deadcode,varcheck
 const (
 	opaTypeNull int32 = iota + 1
 	opaTypeBoolean
@@ -45,10 +45,8 @@ const (
 )
 
 const (
-	opaFuncPrefix        = "opa_"
 	opaAbort             = "opa_abort"
 	opaRuntimeError      = "opa_runtime_error"
-	opaJSONParse         = "opa_json_parse"
 	opaNull              = "opa_null"
 	opaBoolean           = "opa_boolean"
 	opaNumberInt         = "opa_number_int"