Backport fuzzing support

Summary:
Essentially backport snippets of the following commit:
golang/go@33c89be

Gives us support for Go fuzzing: https://go.dev/doc/security/fuzz/

#build_rule_type[go_library,go_binary,go_unittest,go_test]

Reviewed By: inesusvet

Differential Revision: D68397313

fbshipit-source-id: e94da245be2c1a761206869a99255effcb320fe4

prelude/go_bootstrap/tools/go/testmaingen.go

@@ -203,7 +203,7 @@ type Package struct {
 }
 
 // isTestFunc tells whether fn has the type of a testing function. arg
-// specifies the parameter type we look for: B, M or T.
+// specifies the parameter type we look for: B, F, M or T.
 func isTestFunc(fn *ast.FuncDecl, arg string) bool {
 	if fn.Type.Results != nil && len(fn.Type.Results.List) > 0 ||
 		fn.Type.Params.List == nil ||
@@ -218,7 +218,7 @@ func isTestFunc(fn *ast.FuncDecl, arg string) bool {
 	// We can't easily check that the type is *testing.M
 	// because we don't know how testing has been imported,
 	// but at least check that it's *M or *something.M.
-	// Same applies for B and T.
+	// Same applies for B, F and T.
 	if name, ok := ptr.X.(*ast.Ident); ok && name.Name == arg {
 		return true
 	}
@@ -286,6 +286,7 @@ type coverInfo struct {
 type testFuncs struct {
 	Tests       []testFunc
 	Benchmarks  []testFunc
+	FuzzTargets []testFunc
 	Examples    []testFunc
 	TestMain    *testFunc
 	Package     *Package
@@ -377,6 +378,13 @@ func (t *testFuncs) load(filename, pkg string, doImport, seen *bool) error {
 			}
 			t.Benchmarks = append(t.Benchmarks, testFunc{pkg, name, "", false})
 			*doImport, *seen = true, true
+		case isTest(name, "Fuzz"):
+			err := checkTestFunc(n, "F")
+			if err != nil {
+				return err
+			}
+			t.FuzzTargets = append(t.FuzzTargets, testFunc{pkg, name, "", false})
+			*doImport, *seen = true, true
 		}
 	}
 	ex := doc.Examples(f)
@@ -452,6 +460,9 @@ var benchmarks = []testing.InternalBenchmark{
 }
 {{if .ReleaseTag "go1.18"}}
 var fuzzTargets = []testing.InternalFuzzTarget{
+{{range .FuzzTargets}}
+	{"{{.Name}}", {{.Package}}.{{.Name}}},
+{{end}}
 }
 {{end}}
 var examples = []testing.InternalExample{